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The document "Grand Challenges in Heat Decarbonisation" discusses the significant role of heat in global energy consumption and the urgent need to decarbonize heat supply to achieve net zero greenhouse gas emissions by 2050. It highlights various challenges and alternative technologies for domestic heating, such as heat pumps, biomass boilers, and solar energy, emphasizing the importance of transitioning to low or zero carbon heating technologies. The document also addresses industrial heating challenges and the research perspectives on high temperature industrial heat pumps to recover waste heat and reduce GHG emissions in industrial processes. [Extracted from the article]

Exposure to ambient particulate matter (PM) is one of the leading health risks globally. Several European regions experience high PM concentrations due to the burning of fossil fuels for domestic heating. Accordingly, Serbia ranks among the countries with the highest levels of air pollution. The annual mean concentrations are the most common indicator in exposure studies. However, this study uses station data in Serbia to indicate the concentrations to which the population is exposed during the heating season (October–April) based on daily PM10 and PM2.5 concentrations from 2011 to 2022. In addition, events with concentrations above WHO-recommended daily upper limits (45 μg/m3 for PM10 and 15 μg/m3 for PM2.5) are classified by duration, intensity, and the cumulative sum of excess concentrations. The highest daily mean PM10 concentration in the heating season is 87.1 μg/m3, and for PM2.5, the highest concentration is 65.6 μg/m3 (up to three to four times more than in the rest of the year in both cases). During the most extreme events, mean daily PM10 and PM2.5 concentrations were in the ranges of 150–200 μg/m3 and 100–150 μg/m3, respectively. The cumulative sum of excess concentration in the most extreme events reached up to ~7600 μg/m3 for PM10 and ~5000 μg/m3 for PM2.5. To better understand the problem, the share of occupied dwellings with heating installations and prevailing types of fuels were explored on the municipal level. In general, in most municipalities in Serbia, the share of dwellings with heating installations is up to 60%. Among those, dwellings with district heating dominate, while only a small number of them have a significant share of central heating. When it comes to fuel types, wood is primarily used in dwellings with district heating or without heating installations. These findings imply directions for the development of air quality planning and management policies. [ABSTRACT FROM AUTHOR]

Thermoacoustic heat pumps are a promising heating technology that utilizes medium/low-grade heat to reduce reliance on electricity. This study proposes a single direct-coupled configuration for a thermoacoustic heat pump, aimed at minimizing system complexity and making it suitable for domestic applications. Numerical investigations were conducted under typical household heating conditions, including performance analysis, exergy loss evaluation, and axial distribution of key parameters. Results show that the proposed thermoacoustic heat pump achieves a heating capacity of 5.7 kW and a coefficient of performance of 1.4, with a heating temperature of 300 °C and a heat-sink temperature of 55 °C. A comparison with existing absorption heat pumps reveals favorable adaptability for large temperature lift applications. A case study conducted in Finland over an annual cycle analyzes the economic and environmental performance of the system, identifying two distinct modes based on the driving heat source: medium temperature (≥250 °C) and low temperature (

Electric (mechanical vapour-compression) heat pumps are acknowledged as a key technology for heat decarbonisation, their role being evidently more significant than thermally driven heat pumps and hydrogen boilers. The International Energy Agency estimates that, assuming governments meet their commitments, the global capacity of electric heat pumps will nearly triple by 2030. Heat pump systems come in a variety of designs, including system configurations, component (e.g., heat exchanger, compressor, working fluid) selection, and operation strategies that have a significant effect on performance and cost. In this article, we review current progress in technology development and in the methods used for techno-economic performance assessments of domestic (i.e., residential) heat pumps in the range of a few ∼kWs. The principles upon which heat pump operation and performance depend are first stated. Then, drawing from widely used performance indicators and published data on hundreds of commercially available heat pump products and components over a wide range of operating conditions, a detailed methodology is presented for obtaining performance and cost estimates. A synopsis of potential synergies with other heating, cooling and storage technologies is presented, demonstrating that appropriate integration and operation are required to maximise cost-effectiveness and emission reduction capabilities. Furthermore, whole-energy system implications of widespread heat electrification and current policy measures supporting electric heat pumps in different countries are discussed. The models and analyses presented in this review are useful to a diverse set of stakeholders, including energy technology and system modellers, technology manufacturers, end-users, government, and policy makers.

• A 2 kW-class FPSHP prototype was designed, built and tested. • The analysis of the distribution of acoustic field and exergy loss were carried out. • The influence of key parameters was studied by simulation and experiment. • The prototype can provide 2253 W of heating with a COP h of 2.76. Compared with conventional vapour-compression heat pump technology, the free-piston Stirling heat pump technology attracts wide attention for its high efficiency, reliability, and environmental friendliness. In this work, a free-piston Stirling heat pump prototype with a two-kilowatt capacity, which can operate with an outside ambient temperature ranging from -20 to 10 °C, was designed, built and tested. First, numerical simulations were carried out to explore the distributions of the acoustic field and exergy loss. Second, the effects of several operating parameters on the heating performance were numerically investigated in detail. Finally, to validate the accuracy of the simulation results, verification experiments were conducted on the experimental platform of a free-piston Stirling heat pump driven by a dual-opposed linear compressor. Experimental data show that with a hot-end temperature of 45 °C and outside ambient temperature of 0 °C, the prototype achieved a heating capacity of 2253 W with a corresponding COP h of 2.76 (based on PV power input) and a relative Carnot efficiency of 39.1 %; in particular, the prototype was able to achieve a COP h of 2.5 when pumping heat from -20 °C to 45 °C for 3.25 MPa mean pressure. The simulation and experimental results demonstrated that the free-piston Stirling heat pump system has good potential to achieve high efficiency as a heating supply in a cold region. [ABSTRACT FROM AUTHOR]

Summary: Air-to-water heat pumps come with diverse design options whose cost and performance are correlated, giving rise to a crucial question: should manufacturers aim at designing higher-performance yet higher-cost heat pumps, reducing the wider energy infrastructure cost but increasing the upfront cost to end users, or more affordable yet lower-performance alternatives? Comprehensive heat pump performance and cost models are integrated within a whole UK energy system framework to capture how different heat pump designs influence the decarbonization pathway. We find that an uptake of higher-performance heat pumps leads to a reduced national electricity generation capacity. However, there is an optimal design that minimizes the total system transition cost, indicating a point of diminishing returns, beyond which, instead of investing in even higher heat pump performance, it is more cost effective to invest in centralized energy generation and storage. Insights are valuable for locations with low heat pump adoption and high electricity-to-gas price ratios. Science for society: Reducing the carbon footprint associated with domestic heating remains a challenge in many economies. Whole-energy system models are used to identify national decarbonization pathways, but many of them share a limitation: the cost and performance of competing technologies, especially with respect to heating, are represented by single efficiency and cost values or simplified models. In this work, detailed models that capture the cost and performance characteristics of heat pumps for different designs are integrated within a whole-energy system model. This integration extends the capabilities of the system model: besides optimizing network infrastructures, it also provides information on the optimal technology designs required to meet the system-wide objectives. Our findings reveal that there is an optimal heat pump design that minimizes the system transition cost. Further performance improvements increase overall costs, favoring investment in centralized energy generation and storage.

Decarbonisation in moderate and cold climates is reliant on the replacement of existing heating technologies with electric heat pumps. Heat pumps work differently from incumbent technologies, including in how they are controlled, their distribution of heat around the home and their space requirements. Despite evidence that domestic practices and interests associated with women played an important role in previous heating transitions, policy and research have not yet considered how heat pumps might interact with traditionally gendered needs and concerns. This could have significant implications for the success of the heat pump transition. This synthesis uses a framework of evidenced heating needs, incorporating wellbeing, resources, ease of use and relational dynamics, to structure a narrative literature review on how experiences of heat pumps may be gendered. Indicative evidence suggests that heat pumps have the potential to improve female thermal comfort, but that other possibly gendered heating needs such as minimising perceived waste and easy controllability are not always addressed. Amidst a lack of empirical studies exploring women’s needs, and whether they are met by heat pumps, a series of recommendations is provided for multidisciplinary research on the topic and to enhance consideration of gendered needs and experiences in policy development. Policy relevance Ensuring that heat pumps, and strategies designed to promote them, cater to diverse preferences and needs could support the current energy transition. This paper specifically considers experiences and practices traditionally understood as women’s priorities. Despite these playing a key role in previous heating transitions, current policy and industry strategies designed to support the heat pump transition have not yet taken gender into account. In addition, this article demonstrates that how traditionally female practices and experiences mingle with the use of heat pumps has not been taken into account in research, and that empirical evidence on this is currently limited. Consequently, policymakers urgently need to support a strengthening of the evidence base on gendered aspects of heat pump adoption and use. Against such evidence, heat policy can more fully consider and engage women, ultimately contributing to the success of the heat pump transition.

Space heating and hot water supply usually have great energy consumption in terms of household, industry, and other services which could be a big issue especially for the cold region. From technical and economic aspect, the present work investigates a hybrid sorption heat transformer (HSHT), which also plays a role of energy storage and upgrade. A renewable source or off-grid electricity is used for electricity supply while solar heat or ambient heat is regarded as heat inputs for two different scenarios. Composite ammonium chloride is used for further analysis of HSHT. Results indicate that HSHT could be a good candidate for the domestic heating in the cold region. Compared with vapor compression heat pump (VCHP), payback period (PBP) of HSHT could be reduced by up to 40%. Under different scenarios, PBPs are in the range from 2.48 year to 4.1 year. Also the levelized costs of heating of HSHT ranges from 20 $·MWh−1 to 46 $·MWh−1 for scenario 1 while the values of 64–133 $·MWh−1 could be obtained for scenario 2 which is up to 35.6% lower than that of VCHP. Carbon emission of HSHT system only accounts for 18% and 11% of that of gas boiler and VCHP, respectively. [ABSTRACT FROM AUTHOR]

The answer to covering the energy demand of society by increasing the share of renewables must come from the conjunction of several technologies. A preliminary study on the feasibility of anaerobic digestion in residential housing and buildings was carried out, considering a mix of novel and traditional technologies. Different scenarios were evaluated for developed and developing countries, considering small communities and single housing configurations. Anaerobic digestion produces biogas to be used for cooking or heat production, thus aiding in covering the energy demand of residents. There are several aspects still pending a solution regarding medium and small-scale digestion applications under a decentralized waste configuration. The increase in reactor productivity is essential, but social aspects must be considered as well to prevent nuisance caused by offensive odors and legal responsibilities when community digesters create inconvenience to neighbors. Results indicated that using anaerobic digestion to treat residential food and garden waste under a decentralized configuration could scarcely cover 5.8% of the domestic heating demand for highly populated residential urban areas. This value may be increased if assumptions of maximum methane yields are considered, reaching up to 17%. Biological processes may be integrated into a mixed energy production approach, but higher yields are needed to make it realistic. Factors regarding levelized energy production costs are to be carefully considered. Large-scale systems are intrinsically more efficient than small-scale devices, thus making it crucial to establish a critical equilibrium between public acceptance and the scale of technology application.

The objective of this research was to investigate utilizing small to medium-scale wind energy in domestic heating without considerable losses by direct conversion of the wind energy to thermal energy through a hydraulic medium. For this purpose, the virtual wind turbine mathematical model was developed in Simulink. Using hardware-in-the-loop (HIL) simulation, the Simulink model was integrated with dSPACE to control the AC motor connected to a variable displacement pump. The speed of the motor was controlled using a frequency converter, to which the torque of the virtual turbine model was supplied in real-time, and the angular velocity of the motor was fed back to the system. By regulating the valve orifice, a pressure drop was created across the orifice area, which led to the generation of thermal power. In order to validate the real-time simulated turbine, the output power and the characteristic curve of the tip speed ratio (λ) based on the power coefficient (CP) resulted from the real-time simulation were reconciled with the corresponding curves of the real turbine. The results demonstrated the conformity of the real-time simulation with the real turbine. The thermal power produced was measured by measuring the temperature of the hydraulic oil.

• Ultra-low temperature heating of dual-source heat pump with concentrated collector has been studied. • Using concentrated collector can improve response speedy of ultra-low temperature heating. • Ultra-low temperature heating improves application of renewable energy and saves electricity by 15.4%. • Ultra-low temperature heating increases heat provision from passive heating by 6.4%. The fifth-generation heating – ultra-low temperature heating benefits to reduce electricity consumption and achieve the net zero goal. The dual-source solar assisted heat pump based heating system has been demonstrated to be an attractive green heating technology for the domestic sector. However, the slower response speed of the low temperature heating to the variation of heating load in responding to the variations of weather conditions limits its thermal comfort performance. The enhancement in solar collector performance brings valuable improvements in response speed of the heating system. In the present work, a heating system based on solar assisted air source heat pump using a compound parabolic concentrator-capillary tube solar collector (CPC-CSC) is investigated with the set heating temperatures of 40, 45, 50, and 55 °C. This heating system works for both space heating and hot water under the weather conditions in London. The results suggest that using a concentrated solar collector improves the response speed of the heating system at low set heating temperatures. For such a heating system, the ultra-low heating temperature increases the application of renewable energy and passive heating (by 6.4%). Compared with the dual-source indirect expansion solar assisted heat pump using flat plate collector, the heating system using CPC-CSC can reduce TEWI by 4.6% with a slightly longer (1.9%) payback period. As the set heating temperature decreases from 55 to 40 °C, the seasonal and yearly system seasonal performance factors significantly increase by 17.1% and 20.5%, respectively. [ABSTRACT FROM AUTHOR]

The utilisation of waste wood from furniture production brings new problems connected with an incomplete thermochemical decomposition of additives (chemicals for improving properties of plastics) in small heating with the addition of sources. Unique organic compounds produced by the combustion of waste wood allow the identification of the type of fuel. The organic compounds contained in the char deposits were analysed by pyrolysis gas chromatography with mass spectrometry. The deposits from the combustion of briquettes from furniture production contain organic compounds originating by decomposition of phenolic resins, aminoplasts (urea–formaldehyde, resorcinol–formaldehyde and melamine), polyurethanes and wood glue. Additives contained in the deposits include plasticisers such as phthalates (DEHP, dibutyl phthalate and diisobutyl phthalate), flame retardants (2-propanol, 1-chlorophosphate (3:1) and p-terphenyl). Deposits from the combustion of briquettes from virgin wood do not contain these compounds. The total amount of compounds identified in the deposits from the boiler, which do not come from virgin wood combustion, varies in the range between 4.25 and 6.25 g/kg. Phthalates (55.5%) and PVAc adhesives (18.6%) are the main anthropogenic compounds in the deposits from domestic boilers. [ABSTRACT FROM AUTHOR]

Decarbonisation in moderate and cold climates is reliant on the replacement of existing heating technologies with electric heat pumps. Heat pumps work differently from incumbent technologies, including in how they are controlled, their distribution of heat around the home and their space requirements. Despite evidence that domestic practices and interests associated with women played an important role in previous heating transitions, policy and research have not yet considered how heat pumps might interact with traditionally gendered needs and concerns. This could have significant implications for the success of the heat pump transition. This synthesis uses a framework of evidenced heating needs, incorporating wellbeing, resources, ease of use and relational dynamics, to structure a narrative literature review on how experiences of heat pumps may be gendered. Indicative evidence suggests that heat pumps have the potential to improve female thermal comfort, but that other possibly gendered heating needs such as minimising perceived waste and easy controllability are not always addressed. Amidst a lack of empirical studies exploring women's needs, and whether they are met by heat pumps, a series of recommendations is provided for multidisciplinary research on the topic and to enhance consideration of gendered needs and experiences in policy development. [ABSTRACT FROM AUTHOR]

The answer to covering the energy demand of society by increasing the share of renewables must come from the conjunction of several technologies. A preliminary study on the feasibility of anaerobic digestion in residential housing and buildings was carried out, considering a mix of novel and traditional technologies. Different scenarios were evaluated for developed and developing countries, considering small communities and single housing configurations. Anaerobic digestion produces biogas to be used for cooking or heat production, thus aiding in covering the energy demand of residents. There are several aspects still pending a solution regarding medium and small-scale digestion applications under a decentralized waste configuration. The increase in reactor productivity is essential, but social aspects must be considered as well to prevent nuisance caused by offensive odors and legal responsibilities when community digesters create inconvenience to neighbors. Results indicated that using anaerobic digestion to treat residential food and garden waste under a decentralized configuration could scarcely cover 5.8% of the domestic heating demand for highly populated residential urban areas. This value may be increased if assumptions of maximum methane yields are considered, reaching up to 17%. Biological processes may be integrated into a mixed energy production approach, but higher yields are needed to make it realistic. Factors regarding levelized energy production costs are to be carefully considered. Large-scale systems are intrinsically more efficient than small-scale devices, thus making it crucial to establish a critical equilibrium between public acceptance and the scale of technology application. [ABSTRACT FROM AUTHOR]

Transitioning from predominantly natural gas domestic heating to low carbon heating is one of the major challenges of the UK's net zero decarbonisation pathway. Compact wall-hung combination boilers are the dominant heating appliance and continue to be installed as a rate of over 1.5 million per year, compared to less than 50 k per year for Heat Pumps. The disparity persists despite repeated Government support in the form of the Renewable Heat Incentive and the Green Homes Grant. Compact hybrid appliances offer a technology solution similar to the current combination boiler in terms of size and performance, which could be attractive to consumers. However, there is currently little knowledge of the emissions savings that could be achieved in practice by compact hybrid appliances. This research systematically analyses real world high frequency boiler data to evaluate the potential of such appliances to make carbon savings while emulating combination boiler operation. By utilising high frequency diagnostic data from combination boilers, the disaggregated (hot water and heating) demand is mapped onto hybrid models to determine the energy and emission impact. Exploration of the relative power output of the HP and boiler components of the modelled hybrid appliances provides insight into the appropriate specification of compact hybrids which can deliver similar heat service to boilers while maximising emissions savings. The analysis shows that hybrid appliances with moderately sized HPs can significantly contribute to the decarbonisation of the homes considered in the study. Considerable disruption could be avoided in retrofit due to the physical size of the proposed heat pump and ability of the hybrid system to operate with the existing heat emitter network. [ABSTRACT FROM AUTHOR]

• Low temperature heating of solar assisted air source heat pump heating systems has been studied. • Low temperature heating enables reduction in electricity consumption by up to 19.1%. • Low temperature heating results in increase in COP of heat pumps by 12% to 18%. • Low temperature heating leads to increase in seasonal performance factor by up to 19.1%. Reducing electricity consumption is of great importance by improving the operation performance of the heating systems based on solar-assisted air source heat pumps for domestic heating. The set hot-water-supply temperature of the heating system affect both the system operation performance and the indoor thermal comfort condition. The effect of low temperature heating on the system operation performance is investigated to figure out the way to significantly save electricity. A single-family house is chosen as the reference building and the heating system is modelled and simulated under the weather conditions in the locations of London, Aughton and Aberdeen in the UK over a year. The set hot-water-supply temperatures are taken to be 40 °C, 45 °C, 50 °C and 55 °C. For the heating systems, with the decrease in set hot-water-supply temperature from 55 °C to 40 °C, the yearly seasonal performance factor increases by 16.7%, 19.1% and 15.4% in London, Aughton and Aberdeen, respectively. Consequently, the yearly total electricity consumption decreases by 19.1%, 14.9% and 13.3% in London, Aughton and Aberdeen, respectively. The results show that low temperature heating enables significant reduction in electricity consumption of such heating systems. [ABSTRACT FROM AUTHOR]

Recent work analytically investigates the heat transfer characteristics of a three fluid heat exchanger used for domestic heating applications with respect to different design parameters, i.e. flow rate, inlet temperature, tube diameter, coil diameter, and coil pitch. The present and previous results are compared with the literature. Overall agreement among these results are observed with little variation. Afterwards, the present temperature data was verified with prior experimental data and little deviation observed in these results vary from -4.28 % to +6.68 % and -6.17% to +5.92% in parallel and counter flow configuration, respectively. It is ensued that the coil side Nusselt number increases with the rise in coil side fluid flow rate and inlet temperature, coil outside fluid inlet temperature and coil diameter respectively. The increment in coil side flow rate and inlet temperature are identified as the major contributors, with 297% and 39.5% contributions. Similarly, growth in coil outside Nusselt number is observed with the rise in coil side fluid inlet temperature and flow rate, coil outside fluid flow rate and inlet temperature, and coil pitch respectively. The coil pitch and flow rate at the coil outside are identified as major contributors with 36% and 28.5% contribution repsectively. Distinct correlations for heat transfer in the present HEx are proposed for coil inside and outside fluid flow in a turbulent flow regime. The developed correlations results are compared with the present result, and reasonable agreement is observed within the data range of +13% to -14% and +10% to -11% for coil inside and outside Nusselt number, respectively. [ABSTRACT FROM AUTHOR]

The study provides new insights on the empirical facts and figures of Acacia Mangium graded wood pellets in non-industrial thermochemical applications. The test material was characterized according to normative solid biofuel specifications that confirmed a relevant net calorific value, a considerable mass fraction of the ash content, and the sign of ash softening initially observed at a notable temperature. The instrument readings of six major combustion gaseous components and particulate matter in the exhaust gas verified consistent emission profiles of woody solid biofuels in small-scale combustion installations. The calculated values of CO, CO 2 , NO, SO 2 , TOC and PM were analyzed in depth. The emission characteristics obtained revealed the apparent correlations of the fractions of gaseous components subjected to the elemental content determined by the ultimate analysis of Acacia Mangium wood pellets. The particulate matter emitted containing unburnt carbonaceous solid residues and inorganic materials remaining as byproducts were comparatively evaluated according to the different fuel types and variable test devices in earlier works. The mechanism of production and removal of volatilized alkali metals that influence solid particle formation was discussed. The excessive amount of ash-forming elements could potentially cause uncertain fluctuations in emission characteristics, which were remarked upon by further ash-related investigations requiring additional analysis. [ABSTRACT FROM AUTHOR]

Most cities worldwide suffer from serious air-quality problems, which have received increasing attention in the past decade. The most probable reason for the air-quality problems is the urban population growth, combined with a change in land use due to increasing urban areas. The emission of air pollutants is caused by different anthropogenic processes which can be categorized into the sources of urban traffic, industry, and domestic heating. Dispersion and dilution of air pollutants are strongly influenced by meteorological conditions, especially by wind direction, wind speed, turbulence, and atmospheric stability. With an increasing number of people living in cities, there is the need to examine the correlation between air pollution, local climate, and the effects these changes have on global climate. New interdisciplinary research studies are needed to increase our understanding of the interactions among these aspects. The aim is to analyze the pollutant condition in Rome and the other provinces of the Lazio region with qualitative and quantitative analysis, in order to understand which are the main pollutant sources and what is the correlation of habits of the population on air pollutant emissions. [ABSTRACT FROM AUTHOR]

Winter season is the time of increased emission of exhaust gases from household heating appliances containing particulate matter (PM) and other noxious contaminants. Many old buildings and single houses, particularly at rural and small town regions, still use stoves, fireplaces or ovens to flat heating. Besides qualified fuels like coal or biomass pellets, all kinds of wastes are also burned in many cases, producing not only mineral particles but also toxic volatile organic compounds or other carcinogenic species. To solve the problem of high level of emission of solid particles and organic-compound molecules different constructions of electrostatic precipitators, which can remove such particles, have been developed in last two decades, which were designed to operate downstream of small domestic boilers. Such electrostatic precipitator must comply with the ECODESIGN emission limits, which set the emission level at 20 mg/m3, for biomass. The mass collection efficiency should be higher than 95 % to obtain this emission level. This brief review presents different constructions of electrostatic precipitators designed to be used for the removal of fly ash particles from domestic heating appliances. • Domestic heating appliances are the main source of PM contaminants during winter season. • Electrostatic precipitators allow old furnaces and boiler to comply with ecodesign requirements. • Boiler-integrated, boiler-attached and chimney-top are the main constructions of electrostatic precipitators. • Fouling and cleaning of electrodes and insulators are the main issues in using domestic electrostatic precipitator. [ABSTRACT FROM AUTHOR]

In the UK, heating systems are the most prominent contributor to residential energy demand, with about 80% of the share. Their representation has thus been at the core of all UK-focussed Housing Stock Energy Models (HSEMs). However, these HSEMs estimate heating demand based on monthly or annual energy balances, with correspondingly approximate representations of heating systems and practices (incl. energy conversion, distribution and spatiotemporal control). This paper describes an extension to the dynamic HSEM: EnHub, to rigorously simulate space heating and hot-water components (i.e. heaters, boilers, pumps, radiators, end-point registers, thermostats, taps). Baseline simulations estimate the English housing stock's energy use as 35.9 mtoe. Alternative scenarios in which heating systems are substituted across the board to district heating or ground-source heat pumps predict a reduction in demand to 30 and 18 mtoe respectively; the latter potentially being zero-carbon if the power sector is successfully decarbonised. Abbreviations ASHP: Air Source Heat Pump; BREDEM: Building Research Establishment Domestic Energy Model; CHM: Cambridge Housing Model; DHW: domestic hot water; EHS: English Housing Survey; EnHub: housing stock Energy Hub; GSHP: Ground Source Heat Pump; GUI: Graphical User Interface; HDD: Heating Degree Day; HSEM: Housing Stock Energy Model; idf: EnergyPlus Input Data File; IEA: International Energy Agency; LHS: Latin Hypercube Sampling; NEED: National Energy Efficiency Data-Framework; SAP: Standard Assessment Procedure; SH: space heating; UK: United Kingdom [ABSTRACT FROM AUTHOR]

Northern China suffers from serious air pollution especially in winter, much of which derives from solid fuel used for domestic heating in rural areas. In order to reduce pollution emissions in the heating season, the Chinese government has introduced a "coal-to-gas conversion" policy, promoting a switch to natural gas which is much cleaner than the coal normally used for winter heating. The "coal-to-gas conversion" project will cover more than 1.8 billion m2 of heated built floor area and affect more than 12 million heat users in Beijing, Tianjin, Hebei, and the surrounding areas. Life cycle assessment and life cycle cost methods are applied to compare and analyze the environmental impact and economic cost of household energy usage for the whole year under 5 scenarios before and after "coal-to-gas conversion." In the three scenarios after "coal-to-gas conversion," the environmental impact decreases by around 50% while the total economic cost increases by around 80%. Particulate emissions responsible for air pollution are considerably reduced with accompanying benefits for human health, though significant, but reduced, impacts on freshwater and marine ecotoxicity remain. Improving thermal efficiency through natural gas utilization, implementing an energy-saving retrofit of rural housing, and promoting straw utilization yield benefits for people and the environment in rural areas of northern China. [ABSTRACT FROM AUTHOR]

• Energy poverty measurement developed for the Nordic context. • Objective and subjective energy poverty occurs in different housing settings. • Heat pumps and solid wood heating alleviate energy poverty risk in Finland. • Women, families with children and households using oil heating are more vulnerable. Vulnerability to energy poverty occurs when a household has difficulties to meet adequate energy service levels. Recent energy crises manifested the consequences of energy vulnerability also in the Nordic countries. This study brings evidence on energy poverty in Finland, using a large household energy survey dataset (N = 4,295). The ten-per-cent limit threshold is used to measure objective energy vulnerability and the subjective measure is based on the regularity of households' self-assessed psychological burden regarding their energy expenditures. In our dataset, 18 % of households in detached and semi-detached houses were objectively energy poor and 27 % felt a regular energy-cost burden. Heating type, building age, education level and gender were significant determinants. Ownership of a ground-source heat pump and usage of solid wood reduces winter energy poverty in Finland. Women, particularly in older age groups were significantly more vulnerable than men. For some groups, objective and subjective measurement produced distinctively different results. Households using oil heating in a hybrid heating arrangement were more vulnerable in the objective measurement but they did not feel a similar subjective energy cost burden. Families with children felt subjectively more burdened by their energy expenses than other groups, but they were not more energy-poor along the objective measurement. This is one of the first energy vulnerability studies based on large amount of citizen survey data in Finland and we recommend that further research focuses particularly on how different social groups can access and use different heating installations as this is a key determinant of energy vulnerability in countries with substantial domestic heating energy needs. [ABSTRACT FROM AUTHOR]

Vertical profiling of aerosol particles was performed during the PANhellenic infrastructure for Atmospheric Composition and climatE chAnge (PANACEA) winter campaign (10 January 2020–7 February 2020) over the city of Ioannina, Greece (39.65° N, 20.85° E, 500 m a.s.l.). The middle-sized city of Ioannina suffers from wintertime air pollution episodes due to biomass burning (BB) domestic heating activities. The lidar technique was applied during the PANACEA winter campaign on Ioannina city, to fill the gap of knowledge of the spatio-temporal evolution of the vertical mixing of the particles occurring during these winter-time air pollution episodes. During this campaign the mobile single-wavelength (532 nm) depolarization Aerosol lIdAr System (AIAS) was used to measure the spatio-temporal evolution of the aerosols’ vertical profiles within the Planetary Boundary Layer (PBL) and the lower free troposphere (LFT; up to 4 km height a.s.l.). AIAS performed almost continuous lidar measurements from morning to late evening hours (typically from 07:00 to 19:00 UTC), under cloud-free conditions, to provide the vertical profiles of the aerosol backscatter coefficient (baer) and the particle linear depolarization ratio (PLDR), both at 532 nm. In this study we emphasized on the vertical profiling of very fresh (~hours) biomass burning (BB) particles originating from local domestic heating activities in the area. In total, 33 out of 34 aerosol layers in the lower free troposphere were characterized as fresh biomass burning ones of local origin, showing a mean particle linear depolarization value of 0.04 ± 0.02 with a range of 0.01 to 0.09 (532 nm) in a height region 1.21–2.23 km a.s.l. To corroborate our findings, we used in situ data, particulate matter (PM) concentrations (PM2.5) from a particulate sensor located close to our station, and the total black carbon (BC) concentrations along with the respective contribution of the fossil fuel (BCff) and biomass/wood burning (BCwb) from the Aethalometer. The PM2.5 mass concentrations ranged from 5.6 to 175.7 μg/m3, while the wood burning emissions from residential heating were increasing during the evening hours, with decreasing temperatures. The BCwb concentrations ranged from 0.5 to 17.5 μg/m3, with an extremely high mean contribution of BCwb equal to 85.4%, which in some cases during night-time reached up to 100% during the studied period.

Most cities worldwide suffer from serious air-quality problems, which have received increasing attention in the past decade. The most probable reason for the air-quality problems is the urban population growth, combined with a change in land use due to increasing urban areas. The emission of air pollutants is caused by different anthropogenic processes which can be categorized into the sources of urban traffic, industry, and domestic heating. Dispersion and dilution of air pollutants are strongly influenced by meteorological conditions, especially by wind direction, wind speed, turbulence, and atmospheric stability. With an increasing number of people living in cities, there is the need to examine the correlation between air pollution, local climate, and the effects these changes have on global climate. New interdisciplinary research studies are needed to increase our understanding of the interactions among these aspects. The aim is to analyze the pollutant condition in Rome and the other provinces of the Lazio region with qualitative and quantitative analysis, in order to understand which are the main pollutant sources and what is the correlation of habits of the population on air pollutant emissions.

Featured Application: Domestic space heating and hot water preparation, solar energy storage. Thermal energy used below 100 °C for space heating/cooling and hot water preparation is responsible for a big amount of greenhouse gas emissions in the residential sector. The conjecture of thermal solar and thermochemical solid/gas energy storage processes renders the heat generation to become ecologically clean technology. However, until present, few pilot scale installations were developed and tested. The present work is devoted to the experimental study of global performance of a pilot scale thermochemical energy storage prototype. Two working modes, namely fixed packed bed and moving bed, were tested using 2.2 kg and 5.5 kg of composite material (silica gel impregnated with calcium chloride) under indoor atmospheric conditions. The global experimental efficiency of a 49l water tank charging process during 75 min was found as high as 0.8–0.85. The energy storage density reached in the fixed bed mode by the material was 158 kWh/m3, while in the moving bed mode it was 2.5 times lower. The reasons for such a difference are discussed in depth in the text. [ABSTRACT FROM AUTHOR]

Abstract The possibility of a relevant contribution of biomass burning for domestic heating to PM 10 in the urban area of Rome was explored. The concentration of levoglucosan was determined for 31 months in Rome and in a nearby peri-urban area. During the cold season it reached several hundreds of ng/m3 at both sites, with a clear inverse relationship with air temperature. During the summer it remained well below 100 ng/m3. Although at the peri-urban station the concentration was about 50% higher than at the urban site, the two seasonal patterns show a very good agreement (R2 = 0.95), pointing at a main contribution of biomass burning in both areas. Additional information came from the comparison of the 2-h time pattern of levoglucosan and the mixing conditions of the atmosphere, evaluated by monitoring natural radioactivity. During the summer levoglucosan concentration followed the pattern of natural radioactivity, indicating a contribution from many small sources scattered on a wide area (wildfires, barbecues, agricultural fires). During the heating season the activity of a source that switched in the early afternoon and switched off before midnight was highlighted. A 2-h delay between levoglucosan time patterns at the peri-urban and the urban site suggests that biomass burning mainly occurs outside Rome and the combustion products are then transported towards the city centre. Biomass burning contribution to PM 10 was estimated as 12% at the peri-urban site and 6.7% inside the city, with relevant implications for the health of the about 2.800.000 citizens living in the urban area of Rome. Graphical abstract Image 1 Highlights • During the winter we measured high levoglucosan concentrations in the area of Rome. • The concentration increased in the early afternoon and decreased after midnight. • In the peri-urban area we measured higher values and a 2-h shift with respect to Rome. • A substantial transport from the peri-urban area to the city centre was recognized. • The average contribution of biomass burning to PM 10 in the urban area was 6.7%. [ABSTRACT FROM AUTHOR]

Conventional heating systems are based either on radiators or on fan coils and the heat transfer process is carried out by convection phenomena in both cases, but with some fundamental differences. Traditional radiators can be considered less efficient compared to fancoils due to the fact that their performance relies on natural convection, a less efficient heat transfer process than forced convection. However, in contrast to fan coils, conventional radiators can operate without the need for mains supply. In this paper, a new heating device based on thermoelectricity, that combines the advantages of both radiators and fancoils, is presented. This new system exploits the heat coming from the heating system to generate electricity, which is consumed in situ to power a fan, eliminating the need for a nearby wall outlet. For this purpose, a laboratory prototype has been built and experimental characterization has been carried out. [ABSTRACT FROM AUTHOR]

Abstract The chance of achieving 12% of renewable energy in heating demand by 2020 has gone, as the current RES share is almost the half of this target. The UK struggle to address this deficit, but it still needs more deployment of renewables. Solar energy has proved its viability and is going to play a significant role in increasing the share of renewable heat in domestic heating demand. What makes it more promising than before is that scientists have dealt with many challenges that weaken its growth. Namely, seasonal thermal energy storage that used to solve the mismatch between surplus solar energy in summer and high heating demand in winter. This study investigates the performance of a fully electrified smart heating system [1] that combines solar photovoltaics, borehole thermal energy storage and heat pumps, and compare the results of different sizes communities in Dundee to track the behaviour of BTES and the whole system. Different Solar Fraction and RES Percentage have been achieved with varying demands of heating and different sizes communities. [ABSTRACT FROM AUTHOR]

This study investigates the preferences of Italian home-owners when choosing a new domestic heating system. The focus is on understanding the influence on consumer choice of a potential label certifying the effect of the heating system on the greenhouse effect. To this end, we designed a survey including a discrete choice experiment and administered it to residents in north-eastern Italy. Our findings reveal that, on average, respondents pay particular attention to the green effect of their purchase. The carbon dioxide reduction label was considered second in terms of importance after cost. Further analysis found that our sample presents three clusters of customers, with intra-cluster homogeneous preferences. The cluster analysis showed that while the initial system costs are considered to varying degrees by the whole sample, the carbon dioxide reduction label was considered important by 79% of respondents (members of clusters 1 and 2). To achieve greater results in reducing the greenhouse effect of the domestic heating sector, a combination of policies should be used simultaneously to achieve greater effectiveness. Our simulations support the hypothesis that policymakers should achieve greater results in terms of reducing the domestic greenhouse gas emissions by applying a combined policy that leverages the importance citizens accord to the different characteristics of a heating system. From our results, the application of a ‘low carbon dioxide ( C O 2 ) emissions’ label will amplify the effect of a subsidy that reduces the initial system costs.

Thermal energy used below 100 °C for space heating/cooling and hot water preparation is responsible for a big amount of greenhouse gas emissions in the residential sector. The conjecture of thermal solar and thermochemical solid/gas energy storage processes renders the heat generation to become ecologically clean technology. However, until present, few pilot scale installations were developed and tested. The present work is devoted to the experimental study of global performance of a pilot scale thermochemical energy storage prototype. Two working modes, namely fixed packed bed and moving bed, were tested using 2.2 kg and 5.5 kg of composite material (silica gel impregnated with calcium chloride) under indoor atmospheric conditions. The global experimental efficiency of a 49l water tank charging process during 75 min was found as high as 0.8–0.85. The energy storage density reached in the fixed bed mode by the material was 158 kWh/m3, while in the moving bed mode it was 2.5 times lower. The reasons for such a difference are discussed in depth in the text.

Compact thermal storage using a hybrid phase change material (PCM) store for domestic heating applications is investigated. The primary focus is on thermal demand during the electrical grid-stress period (16:00 h–20:00 h on winter weekdays) when the primary heat source, a heat pump, is turned off. Though this phenomenon may be evident in other countries, the main focus of this work is on electrical grid-stress in UK conditions. In this work, PCM encapsulated in pipe coils surrounded by water in a hot water storage tank is considered. Two alternative samples of salt hydrate are evaluated experimentally and the results are used to inform system modelling. A new model is proposed for relating the enthalpy and temperature of the PCM during melting and solidification. A compact hybrid store design is proposed and a detailed thermal model of the hybrid store with an air-source heat pump is constructed and applied to an example house. Seasonal energy results compared with a conventional water tank are broadly similar but the hybrid store offers better comfort tracking during grid stress periods – average house temperatures falling below 19 °C for 22.7% of the time with a conventional store but only 5.8% of the time using the hybrid store. [ABSTRACT FROM AUTHOR]

The development of residential energy technologies aims to ensure thermal comfort in an increasingly energy-efficient manner. This development influences everyday practices related to comfort in everyday life in dwellings. Therefore, an empirical analysis of interviews with residents in three types of Danish detached houses, related to the building age, is used to understand how changes in technologies influence residents’ practices and notions of comfort. Detached houses are the most widespread type of housing in Denmark, constituting 44% of the housing stock. The analysis focuses on differences in heating systems between the housing types and shows how changes in technologies and material structures shape the practices of heating and airing. A shift in technology from radiators to underfloor heating was found to make a clear difference in both how houses are heated and thermal comfort is perceived. It is found that changes in material structures of houses consequently change residents’ perceptions of comfort and the related everyday practices. A more nuanced set of notions of comfort is developed in relation to different practices, and specifically the relation between airing and heating practices, as well as the context of seasons and the outdoors. [ABSTRACT FROM AUTHOR]

Professionals involved in organizing and undertaking domestic works, such as extensions, maintenance and refurbishment, have an important role in influencing how homes are configured and how occupants live within them. Despite this, the professional identities of these actors, and their impact on domestic energy use, is often overlooked. In response, this paper argues that one useful way of examining their influence is to consider how professional identities shape everyday working practices in relation to clients. Data from two UK interview and observation studies are combined: one with heating installers and the other with architects. The data are analysed using concepts from Abbott’s ‘system of professions’ framework that focuses on how the routine working practices of professional groups are born of how they see themselves and the tasks for which they are responsible. This comparison provides insights into how these two groups manage their professional ‘jurisdictions’ during their client interactions and what this means for policy-makers and industry representatives hoping to influence their work in pursuit of less carbon-intensive living. It also points to the value of further in-depth studies that explore how the routine management of professional jurisdiction impacts upon domestic energy use in a range of contexts. [ABSTRACT FROM AUTHOR]

Air pollution represents the biggest environmental risk for health. It is so widespread and it represents one of the main problems of the worldwide, especially because it is emitted by so many different types of sources. The pollutants can originate directly by exhausted or they can be formed because of the reaction with the atmosphere. The first one includes particulate matter and gaseous pollutants such as sulfur oxides, nitrogen oxides, and carbon oxides. The second one includes the ozone formed from nitrogen oxides and hydrocarbons, and particulate sulfate and nitrate aerosols created in the atmosphere from sulfur and nitrogen oxide gases. During the entire life course, people are exposed to the pollutants and suffer from different consequences depending on the age. The first nine month of life are generally recognized as more critical than latter time periods. The mortality associated to air pollutant exposure is main related to the concentrations of N O x , ozone, carbon monoxide, sulfur dioxides and particular matter. More than 92% of the world's population lives in places where air quality levels exceed the standards. In 2012, one out of every nine deaths was the result of air pollution-related conditions. In 2016 about 3 million deaths a year were linked to exposure to outdoor air pollution. In the last few years many epidemiological studies have shown associations between air pollutant concentrations and human health. Apart from people, even monuments and artworks can be damaged by pollution, especially in city centres. Furthermore, urbanization modified microclimate conditions of the cities, and, together with traffic and domestic heating, led to a discomfort of living conditions. For these reasons, there is the necessity to improve the research on the impact of pollutant and microclimate conditions inside urban areas. In this work different kinds of pollutants in Rome from 2006 to 2015 were analysed, and different techniques of post elaboration were used. In particular, the attention was focused on statistic and cross statistic techniques in time and space. The results led to describe Rome as spatially and temporally independence regarding pollutant. Even weather changes were studied in relation with pollution. In particular, cross-correlation analysis were done with air temperature, solar radiation, wind direction and velocity, highlighting a strong coupling for the most of cases except for particular matter. [ABSTRACT FROM AUTHOR]

Pollution depends on many natural and human factors. The variation of pollutant and weather changes modify the concentration of pollutant in time and space. In fact, this is not only a local problem, but a regional and even global influence is highlighted. People who moved from the countryside to the cities made the air condition worse, because of the factories activities and the domestic heating. These kinds of pollutants, together with the ones related to the urban traffic, are the base of the air toxicity, which can lead to a lot of health problems. Apart from people, even monuments and works of art can be damaged by pollution, especially in the city centres. Exposure to pollutants is usually higher in cities than in the countryside. The more common pollutants produced at high density urban areas are carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOx), ozone (O3), particulate matter (PM) and benzene (C6H6). The aim of this work is to study the air pollutant level in the city of Rome in order to analyse the emissions from di_erent sources. Furthermore, the pollutant exceeds of the limit of the Directive 2008/50/EC, the main legislation about ambient air quality, was analysed for the period taken into account. [ABSTRACT FROM AUTHOR]

The overall aim of this work is to develop a thermoelectric (TE) heating system powered by renewable energy that could compete, in the future, with current domestic heating system to reduce the greenhouse gas emissions. In this paper, our results suggest that TE modules can potentially be a solution for domestic indoor space heating whilst using renewable electricity. The test results of the space heating application of TE modules in a laboratory environment (19–21 °C) and outside courtyard low-temperature environment (1–5 °C) demonstrate that sufficient temperature difference can be achieved with TE modules so as to satisfy UK thermal comfort levels. The heating COP test results of TE modules also suggest an acceptable heat pump efficiency for the domestic heating application. Consequently and in order to ascertain its potential feasibility, a domestic heating application of TE modules to a Pre-1900s mid-terrace UK dwelling using hybrid renewable energy of solar energy and wind energy is presented. Our calculations suggest that a TE heating system, powered by local hybrid renewable energy and energy storage, can partly meet the domestic heating demand and could achieve a theoretical energy saving efficiency of 64.03% and reduce the CO 2 emission of 4305.40 kg/year compared with using generic electricity radiator for the domestic space heating whilst the average heating COP remains at 1.8. [ABSTRACT FROM AUTHOR]