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The paper presents 3E (energy, exergy and economic) analysis of a modified Kalina power-cooling vapour absorption cycles (KLPCCs) for better thermo-economic figures of merit to drive affordable energy access and climate change mitigation. The analysis presents a balanced technical and economic conclusion in view of resource management and sustainability. The system utilized a Kalina power-cooling system at the topping cycle and an embedded vapour absorption system (VAB) at the bottoming cycle, which is a novelty. In the modified KLPCC, a supplementary evaporator and heat exchangers are integrated with the bottoming cycle. The considered performance indicators include energy efficiency, exergy efficiency, cooling rate, turbine net output, COP, and cost rate. From the results, about 1077 kW cooling rate was produced, while the energy efficiency, exergy efficiency, COP, and turbine output were estimated at 16.97 %, 8.15 %, 0.706, and 291 kW, respectively. The LCC of $ 1.573 million was achieved, with the break-even point and unit energy cost calculated at five years and 0.0134 $/ kWh, respectively. The outcomes are holistic and adequate for policymakers in the field of energy access and environmental sustainability.

In the present paper, the experimental results of the use of R1234yf and R1234ze(E) as drop-in alternatives of R134a in a water-to-water heat pump are discussed. The heat pump is firstly tested with R134a, to establish the baseline performance, and, then, is tested with the two above-mentioned refrigerants considering the same compressor shaft rotational frequency and the same outlet temperatures of the secondary fluids from the evaporator and the condenser. The obtained results show that, compared to the R134a, the use of R1234yf leads to a reduction of the heating capacity and of the COP up to 9.80% and 7.39% respectively, whereas with the use of R1234ze(E) the capacity reduction achieves a maximum of 33.82% while a COP variation in the range −12.27% to +4.32% is found. A second group of tests is carried out varying the rotational frequency of the compressor shaft with the aim of matching the baseline R134a heating capacity. The results indicate an increase in the shaft rotational frequency up to 16% with R1234yf and up to 50% with R1234ze(E) which, however, leads to a maximum reduction of the heat pump COP respectively equal to 7.38% and to 18.11%.

Restrictive environmental regulations are driving the use of CO 2 as working fluid in commercial vapour compression plants due to its ultra-low global warming potential (GWP 100 = 1) and its natural condition. However, at high ambient temperatures transcritical operating conditions are commonly achieved causing low energy efficiencies in refrigeration facilities. To solve this issue, several improvements have been implemented, especially in large centralized plants where ejectors, parallel compressors or subcooler systems, among others, are frequently used. Despite their good results, these measures are not suitable for small-capacity systems due mainly to the cost and the complexity of the system. Accordingly, this work presents a new subcooling system equipped with thermoelectric modules (TESC), which thanks to its simplicity, low cost and easy control, results very suitable for medium and small capacity plants. The developed methodology finds the gas-cooler pressure and the electric voltage supplied to the TESC system that maximizes the overall COP of the plant taking into account the ambient temperature, the number of thermoelectric modules used and the thermal resistance of the heat exchangers included in the TESC. The obtained results reveal that, with 20 thermoelectric modules, an improvement of 20% in terms of COP and of 25.6% regarding the cooling capacity can be obtained compared to the base cycle of CO 2 of a small cooling plant refrigerated by air. Compared to a cycle that uses an internal heat exchanger IHX, the improvements reach 12.2% and 19.5% respectively. The authors would like to acknowledge the support of the Spanish Ministry of Science, Innovation and Universities for the funding under the FPU Program (FPU16/05203).

[EN] The capillary tube with a liquid-to-suction heat exchanger (CT-LSHX) is a component that is widely used in household refrigerators. Recent works have indicated that even when measuring subcooled conditions at the condenser outlet, the condition at the capillary tube inlet is a two-phase flow. The present work was dedicated to analyzing the actual refrigerant conditions at the capillary tube inlet and to investigating how full liquid conditions could be achieved. The research was performed using a typical household refrigerator with corresponding fresh food and freezer compartments, replacing the original refrigerant-to-air condenser with a refrigerant-to-water condenser. This allowed, first, the condensation conditions to be controlled and, second, the estimation of the refrigerant conditions at the condenser outlet from the heat exchanger balance. The obtained results indicated the presence of a non-equilibrium two-phase flow, composed of subcooled vapor and subcooled liquid, at the capillary tube inlet, with both liquid and vapor entering the capillary tube as a vortex with small, fast fluctuations of the liquid level. This non-equilibrium indicated that the subcooling, evaluated from the pressure and temperature of the refrigerant at the condenser outlet, was only apparent and did not allow the evaluation of the actual enthalpy. Finally, by using a smaller capillary tube diameter and increasing the compressor speed, full liquid conditions at the capillary tube inlet were achieved. Furthermore, a performance comparison between the original and the new design revealed that the COP was higher with full liquid conditions., In this project, the work of Laetitia Bardoulet was partially supported by the Santiago Grisolia 2015 program, which is funded by the Generalitat Valenciana, with the reference number GRISOLIA/2015/021.

TiO2 nanolubricant has been used in this experimental work to study the performance of domestic air conditioner. Air conditioner capacity was 1 ton and the original system has R22 refrigerant. Three alternate refrigerant blends-Blend 1 (B1) composed of R32 and R22 (75:25 wt%), Blend 2 (B2) composed of R32 and R600a (75:25 wt%) and R32 refrigerant have been used in this experimental work to compare the thermo-physical performance with R22.0.01% and 0.02% volume concentration TiO2 nanolubricant have been used. All the temperatures and pressures of different section have been recorded using K-type thermocouple and pressure gauge respectively. Results showed that the selected blends with nanolubricant have higher COP compared to R22. Numerically, COP has been increased by about 25%–60% for B1 and B2 with nanolubricant and 20%–30% for R32 with nanolubricant compared to R22. R32 has shown maximum response by increasing about 60% of refrigerating effect compared to R22 while B1 and B2 have 45% more refrigerating effect. For compression work R32 with nanolubricant has similar compression work compared to R22 while B1 and B2 have 33% less compressor work required. Energy consumption has also been reduced for the blends with nanolubricant. B1 and B2 consumed 30% and 28% less power compared to R22 with nanolubricant. B1 and B2 with nanolubricant reduced the exergy loss by 40–70% while R32 reduced the exergy loss by 31% compared to R22. Overall, either B1 or B2 can also be used as an alternative of R22 with TiO2 nanolubricant.

The efficiency of R600a an eco-friendly refrigerant with graphene nanolubricant was investigated and compared in a domestic refrigerator with R134a refrigerant a zero Ozone Depleting Potential (ODP) but higher Global Warming Potential (GWP) refrigerant. Type K thermocouples were attached to the refrigerator components to track the temperature of the system. Two pressure gauges were also attached to the compressor to determine the pressure at suction and discharge of the domestic refrigerator. A digital wattmeter was used to measure the refrigerator's compressor power consumption. The results showed the evaporator air temperature and pull-down time of R600a with graphene nanolubricant were lower compared to R134a. A higher COP was achieved with R600a in graphene nanaolubricant with an increase in cooling capacity within the range of 5.2 % to 14.2 % and the power consumption reduced within the range of 8.8 % to 26.4 %. Hence, R600a/graphene nano lubricant can successfully replace R134a/POE oil in a domestic refrigerator system.

In order to meet climate goals, it will be necessary to significantly reduce the greenhouse gases emitted by homes. A key factor in the US is to reduce the on-site combustion of fossil fuels for heating end-uses and to replace this with use of electric heat pump technologies connected to a low-carbon grid. The replacement of natural gas furnaces with electric heat pumps is a key home decarbonization strategy. However, the potential for space heating electrification to reduce greenhouse gas emissions depends on the carbon dioxide equivalent (CO2e) content of the electricity used by the heat pump. This varies considerably depending on the source of electricity, with large state to state variability. Furthermore, household energy costs are likely to be impacted by the electrification of space heating, because retail energy prices for both natural gas and electricity in each state vary by factors of seven and four, respectively. Contractors, energy programs, government and building code officials, as well as consumers need clear indications of the likely CO2e and energy cost impacts of proposed electrification projects, because these will affect decarbonization choices and rationales around scaled heating electrification. Government and utility programs also need to be aware of the likely outcomes of any supported/incentivized measures. In this paper, we investigate these effects by looking at new metrics to analyze the change in CO2e emitted and the cost to meet home heating loads when switching from a natural gas furnace to a heat pump for the contiguous 48 states of the mainland US.

The role of optic flow in the control of balance in persons with Parkinson's disease (PD) has yet to be studied. Since basal ganglia are understood to have a role in controlling ocular fixation, we have hypothesized that persons with PD would exhibit impaired performance in fixation tasks, i.e., altered postural balance due to the possible relationships between postural disorders and visual perception. The aim of this preliminary study was to investigate how people affected by PD respond to optic flow stimuli presented with radial expanding motion, with the intention to see how the stimulation of different retinal portions may alter the static postural sway. We measured the body sway using center of pressure parameters recorded from two force platforms during the presentation of the foveal, peripheral and full field radial optic flow stimuli. Persons with PD had different visual responses in terms of fixational eye movement characteristics, with greater postural alteration in the sway area and in the medio-lateral direction than the age-matched control group. Balance impairment in the medio-lateral oscillation is often observed in persons with atypical Parkinsonism, but not in Parkinson's disease. Persons with PD are more dependent on visual feedback with respect to age-matched control subjects, and this could be due to their impaired peripheral kinesthetic feedback. Visual stimulation of standing posture would provide reliable signs in the differential diagnosis of Parkinsonism.

An analysis of design configurations is proposed for a 5 kW residential space heating split system comparing several low GWP refrigerants (R32, R290, R1234yf, R1234ze, XL41, XL55) as potential alternatives to the most common refrigerants actually used (R410A, R407C, R134a). By means of an ad-hoc model, the system performance has been estimated for several geometrical configurations among those possible according to the current compressor and heat exchangers technology. The configurations complying with geometric and thermodynamic constraints are discussed in terms of opposing criteria: economic (set-up and total costs), thermodynamic (COP) and environmental ones (LCCP). With R32 it is possible to define design configurations that are able to reach the best energetic performances for fixed set-up costs. In the range of low set-up costs solutions, R32 and R410A design options are able to work with the same performance. Particularly, R32 can reach the minimum LCCP value as propane with 15% lower total costs.

The refrigeration and air-conditioning system contribute significantly to building energy consumption. Therefore, it is necessary to develop new technologies that can achieve a higher coefficient of performance (COP). Employing a magnetic field (MF) on the condenser tube (between the condenser outlet and the capillary tube) is a new technique that helps in improving efficiency and cooling capacity of air-cooled vapour compression cycle (VCC) water chiller. In this work, four pairs of the permanent magnet of 3000 G field strength were installed on the condenser tube (between exit of the condenser and inlet of the capillary tube) of the VCC water chiller test setup. The performance of the test setup was compared by applying and removing an MF from the condenser tube to estimate an enhancement in the VCC water chiller system with an MF. Experiments were carried out using R404A as a primary refrigerant in the VCC system. This work discusses the outcomes of magnetic flux applied to the condenser tube at various locations of VCC on COP and power consumption of the water chiller unit. The percentage growth in refrigeration effect ranged between 0.58 and 8.82, and a higher value of the refrigeration effect of 8.82 was found by using the first magnet pair. Experimental outcomes show that compressor power consumption decreased by 4.43% with an increase in the number of magnet pairs from 1 to 4. The VCC system performance was improved by 8.94%. (C) 2017 Elsevier B.V. All rights reserved.

Employing booster heat pumps (BHP) in district heating systems can provide a way to use low temperature heat sources for district heating as they allow locally increasing the water temperature on the user side where necessary. Thereby, it can provide decreased heat loss of a district heating system. This experimental study investigated steady state thermal behavior of a BHP for cases with different forward temperature and different flow rates on the user side. The unit used R134a as working fluid. The results revealed that the Coefficient of Performance (COP) of the BHP system has an optimal value at the studied range. At a forward temperature of 45 °C the heat pump reached maximum COP of 4.95, heating capacity of 15.36 kW, and exergy efficiency of 33.4 %, respectively. Lorenz COP and Lorenz efficiency is ranged from 13 to 27 and 0.16 to 0.26, respectively. Exergy destruction of each component as well as exergy efficiency of BHP used in the proposed system have also been analyzed, which showed that the compressor take the highest the exergy destruction among the components. The exergy efficiency ranged from 24.9% to 33.4% in the considered conditions. The share of exergy destruction of condenser and evaporator were influenced by the heat transfer condition on both sides, which reveals that the BHP can achieve potential performance improvement by better matching heat transfer profile of condenser and evaporator.

This thesis calculated and analyzed the feasibility of EAHE in a building in Tianjin, China through theoretical calculation and numerical simulation. According to the theoretical model, the thermal performance of EAHE were obtained by calculating the soil temperature, the calculated temperature of the soil in intermittent operation, the heat release coefficient of tunnel wall and the heat transfer coefficient during intermittent operation. CFD software was used to model summer operating conditions, the hourly air temperature in July in Tianjin was taken as the air temperature of tunnel inlet, simulated the intermittent operation of EAHE for one week, recorded the average temperature of the soil on the tunnel walls and outlet temperature of the working hours of EAHE, data fitting was carried out for the cooling amplitude in the working period, the numerical simulation results accord with the theoretical calculation values. The results of the study indicate that the higher the inlet air temperature, the greater the temperature drop; the soil around the tunnel walls has the characteristic of reducing temperature; considering the modification of the fan temperature rise, COP in winter is greater than that in summer. The energy-saving effect is more significant in winter.

This paper reports a theoretical study of a conventional vapor compression air conditioner combined with a solar energy source. This system comprises two parts: the cooling mechanism and the solar heat source to operate it. Only the cooling machine part will be considered here, in which the refrigerant temperature leaving the immersed coil inside the storage tank can be calculated directly from the pressure–enthalpy diagram of the operating refrigerant. The investigation has been made using a new low global warming potential refrigerant that belongs to HFO family as an alternative to two high global warming potential refrigerants that belong to HFC family. These are R-1234ze(E) as an alternative to R-134a and R-410A. Comparisons between the classical vapor compression air conditioner and the solar assisted air conditioner and also between the selected refrigerants are investigated. The effects of the refrigerant temperature leaving the storage tank on the main performance parameters such as the coefficient of performance, the gain based on compression work, and the required condenser surface area are discussed.

Because the coefficient of performance (COP) is primarily concerned with the core refrigeration system, using it for optimisation purposes may lead to higher than necessary energy consumption. This hypothesis was studied with a simple equation relating this coefficient to the coefficient of system performance (COSP), and with a software model based on an R404A refrigeration system installed in a supermarket in north east England. In both approaches the condenser fan power usage was excluded from the COP but included in the COSP. The results showed that, especially for part load conditions, optimising the core refrigeration system for minimum power consumption led to an appreciably higher overall energy consumption with the implication that the condenser fan and compressor controls should be developed together. When using this holistic approach it was found that energy savings of 4.5% could have been achieved based on six months' data from the installed system.

A hybrid air-conditioning (A/C) system is proposed which consists of two cycles: (1) an ejector cycle driven by exhausted waste heat; and (2) a compressor A/C cycle. The system can operate under three modes: compressor, hybrid and ejector. Under the hybrid mode, the ejector driven by waste heat reduces the compression ratio (CR) of the compressor and boosts the compressor discharge pressure to the condenser pressure. The governing equations are derived based on energy and mass balances for each component of the system. The performance of the hybrid A/C system under compressor mode and hybrid mode is first analyzed theoretically at design conditions. Then it was tested experimentally through variations of (1) primary pressure from 11 to 23 bar; (2) evaporation pressure from 2.5 to 4.5 bar; and (3) condensation pressure from 9 to 12.5 bar, respectively. The experimental results show that the hybrid system is feasible, and can significantly enhance the performance of the automobile A/C systems, 35.2% COP improvement at the automobile idle conditions and more than 40% COP improvement when the automobile speeds over 80 km/h conditions. The increase of primary pressure and evaporation pressure has a positive effect on system performance while the increase of condensation pressure has a negative effect. The hybrid A/C system has the potential to be adopted in automobiles for the advantages of low cost, durable operation and better energy efficiency NRF (Natl Research Foundation, S’pore) Accepted version

In winter, the air conditioning system of cold climate zones requires more heat. For ground source heat pump system, however, heating capacity is lower than the summer cooling capacity. This paper shows a design of a complex building's ground source heat pump air conditioning system, through testing the water temperatures and flows of the ground source side and load side, measurementing the power consumptions of heat pump unit and water pump in winter, analyzes the COP of unit and system and the influence factors of heat transfer. The results show that efficiency is lower when the heat pump unit operate at lower load, the effect of ground-source-side flow change to unit's heating capacity and COP r is greater than load-side flow change.

Polyamine triazine based Covalent Organic Polymer (COP) was synthesized using catalyst free polycondensation method, called Covalent Diamino Polymer (CDAP). 1,3-diaminopropane was selected as the organic linker and the CO 2 adsorption capacity was studied. CDAP was characterized with Fourier Transform Infra-red spectroscopy (FTIR) and N 2 adsorption desorption measurement. A comparison of the characteristics and CO 2 adsorption capacity was made between COP-1 and CDAP. This study found that the structure of organic linkers greatly influences the properties of organic polymer as well as the CO 2 uptake capability.

Waste heat from engine can be utilized to drive an adsorption cooling system for air conditioning purposes in the vehicle cabin, which not only improves the fuel economy but also reduces the carbon footprint. It is also important to reduce the size of the adsorption bed to adopt the adsorption technology for air-conditioning applications in passenger cars, buses and trucks or even trains. In this article, we present a two stage indirect exhaust heat recovery system of automotive engine employing an effective lumped parameter model to simulate the dynamic behaviors of an adsorption chiller that ranges from the transient to the cyclic steady states. The thermodynamic framework of adsorption chiller is developed from the rigor of mass and energy balances of each component of the system and experimentally confirmed isotherms and kinetics data of various adsorbent–adsorbate pairs. The performance factors are calculated in terms of COP (Coefficient of Performance) and SCP (Specific Cooling Power) for different operating parameters such as cycle time, exhaust gas temperatures, cooling water temperatures and flow rates. From the simulation results, it is found that the exhaust energy of a six cylinder 3000 cc private car is able to produce nearly 3 kW of cooling power for the car cabin. It is also observed that the driving heat source temperature does not remain constant throughout the cycle time unlike the conventional adsorption chiller, and the hot water temperatures as driving source vary from 65 to 95 °C. CaCl2-in-silica gel–water system is found better in terms of COP and SCP as compared with other adsorbents – water systems.

Temperatures in the cities are amplified through the urban heat island effect by an additional 2-4 ̊C. The trapping of solar energy in urban canyons and infrastructural plays the most significant role. But use of air conditioning for cooing during summer months is very prevalent in large cities such as New York, and it converts even more energy (electricity) into heat that is rejected into the external environment. The temperature of the environment actually directly controls the efficiency of the common refrigeration cycle found in air conditioning systems by the second law of thermodynamics. A city, with its complex topography of urban canyons and skyscrapers, produces small microclimates with varying temperatures. This project investigates three urban settings that create microclimates that are detrimental for the efficiency of cooling in New York. First, the overall urban heat island effect, second the effect of roof temperature on rooftop package air conditioning units, and third, the impact of local heat emission from agglomerations of window air conditioners. The efficiency loss is investigated by considering the range of temperature changes that can be observed in the surrounding environment of air conditioning system, and determining the subsequent impact on the Coefficient of Performance (COP). Our COP analyses indicate a range of potential energy increases of around 10% to 70% due to increases in environmental temperature around air conditioners. An analysis of the building stock of New York City showed that the electrical energy demand is potentially increased by these effects by 500 TJ from UHI, 75 TJ from rooftop package units, and 370 TJ from window units., Energy Procedia, 78, ISSN:1876-6102, 6th International Building Physics Conference, IBPC 2015

This research paper assessed the performance of R600a with the base lubricant and Multi-walled Carbon Nanotube (MWCNT) nanolubricant at steady state. It describes the instruments required for measurement of the data parameter and its uncertainties, steps involved in preparing and replacing the MWCNT nanolubricant concentration with base lubricant in vapour compression refrigeration. The system's temperature data was collected at the components inlets and outlets. Pressure data was also registered at the compressor outlet and inlet. The data was captured at 27 °C ambient temperature at an interval of 30 min for 300 min. The experiment includes the experimental data collection, Adaptive Neuro-Fuzzy Inference System (ANFIS) training and testing dataset. The use of ANFIS model is explained in predicting the efficiency of MWCNT nanolubricant in a vapour compression refrigerator system. The ANFIS model also provides statistical output measures such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE), and determination coefficient (R2). The data is useful and important for replacing MWCNT nanolubricant with base lubricant in a vapour compression refrigeration system for researchers in the specialisation of energy-efficient materials in refrigeration. The data present can be reused for vapour compression refrigeration systems simulation and modelling.

In this work, performances of conventional air source heat pump water heater (ASHPWH) and direct expansion solar-assisted heat pump water heater (DX-SAHPWH) under various operating conditions are analyzed to make comparison between the two systems. The DX-SAHPWH system in this study uses a plate type roll-bond solar collector with optimized flow channel as the evaporator, which can take both solar energy and ambient air as the heat source. Performances of both systems are investigated experimentally and numerically. The influences of operating conditions (air temperature, water temperature, solar radiation intensity, et al) are analyzed, and performance comparison under various operating conditions is made between the two systems. Results show that, in clear day conditions, the COP of DX-SAHPWH is obviously higher that of ASHPWH because the solar energy can improve the evaporating temperature of the heat pump obviously; in overcast day conditions (without frost formation), COP of both systems are almost the same; and in night conditions, especially in clear night conditions, the DX-SAHPWH shows poor performance because of the poor convectional heat exchanging performance of the solar collector/evaporator and the radiative heat loss to the night sky. And annual performance analysis shows that the average COP of the DX-SAHPWH system is remarkably higher than the conventional ASHPWH system, especially in winter season.

In order to better master the internal airflow distribution characteristics of photovoltaic thermal (PV/T) collector on air source heat pump (ASHP) system heating performance, CFD software was applied in studying the building-integrated photovoltaic thermal (BIPV/T) sys-tem. A mathematical model of BIPV/T and ASHP integrated heating system was established. Numerical simulation of the system was conducted based on the typical meteorological data in Shenyang area. The influence of the inlet and outlet velocity, internal flow field distribution and temperature field distribution of the BIPV/T system were analyzed on the system thermal efficiency. The relationship between optimal COP and the inlet and outlet velocity of ASHP system was studied. The optimal inlet velocity of the BIPV/T – ASHP integrated system was determined to be 4 m/s, and the COP reached 4.6.

CO2 has low critical pressure and temperature. This gives an opportunity CO2 cycles to work in a transcritical nature where heat rejection and absorption are done at supercritical and subcritical conditions, respectively. However, this characteristic posed some performance issues for CO2 refrigeration cycle such as the pressure and temperature of CO2 becomes independent of one another above the critical point thus specifying the operating conditions would be tough. It is also important to identify the optimum cooler pressure and control it; in order to get high cycle coefficient of performance (COP). Thus, the objective of this paper is to investigate the performance of a transcritical CO2 compression refrigeration cycle for different parameters and evaluate its COP. To achieve that, a refrigeration cycle was modeled using thermodynamic concepts. Then, the model was simulated for various parameters that were manipulated to investigate the cycle performance. Maintaining other operating parameters constant the highest COP was 3.24 at 10MPa gas cooler pressure. It was also observed that the cycle is suitable for air-condition application than refrigeration cycle, as COP increases when the evaporator temperature increases. Simulations were conducted using EXCEL developed program. The results can be used in the design of CO2 refrigeration cycle.

Based on the simulation study of air-ground dual heat source heat pump system in the actual project of an office building in Shenyang, this paper compares and analyzes the operating efficiency of dual heat source heat pump system and single heat source heat pump system in summer and winter. The target project adopts air-ground source heat pump coupling operation for heating in winter, ground-source heat pump operation for cooling in summer. Using software TRNSYS, two heat pump systems simulation models are established respectively. Through simulating the hourly changes of the heat pump COP, analyzing the results of system operation, the feasibility of the system is discussed. Based on the series of work, a conclusion can be drawn, that is, in terms of operating efficiency, the COP of the two systems both satisfy the normal operating demand, but the dual one is more stable and has a higher COP.

Accordingly to the properties of zeotropic mixture R32:R236fa, a novel double-temperature chilling water unit was proposal in this paper, this unit can produce two different temperature of chilled water (such as low temperature is 7 °C, high temperature is 16 °C). An experimental system is established to test the performance of the unit. The paper studied the effects of mass component concentrations of the zeotropic mixture and high - low temperature evaporator's source temperature on the performance of the unit. The results show that, when the inlet water temperature of the condenser is 32 °C, outlet water temperature of the evaporator is 7 °C and 16 °C. The coefficient of performance (COP) of the unit can reach 4.14 when the mass component concentration of R32 is 60% and the COP of the unit increase with the increase of mass component concentration of R32 and the chilled water temperature.

Bulk milk coolers are used to chill the milk from its harvest temperature of 35–4 °C to arrest the bacterial growth and maintain the quality of harvested milk. Milk chilling practices are energy intensive with low coefficient of performance (COP) of about 3.0. Increased energy cost concern encouraged an investigation of heat recovery from bulk milk cooler as one conservation alternative for reducing water heating cost in dairy industry. Heat dissipated to atmosphere through condenser is recovered to improve the energy efficiency of plant. The waste heat is utilized to heat the water which is used to clean the milk processing equipments thus saving thermal or electrical energy used to heat the water separately. Shell and coil type heat exchanger is designed and used to recover the waste heat during condensation process. Heat rejected in condensation process consists of superheat and latent heat of the refrigerant. In this work, attempt has been made to recover complete superheat along with part of latent heat which is a present research issue. The results show that complete superheat and 35% of latent heat is recovered. Heat recovery rate is measured for various mass flow rates. Water is flowing on shell side and refrigerant through tubes. The effectiveness of the heat exchanger is determined and the results achieved are presented in this paper. Significant improvements have been achieved and COP of the system is increased from 3 to 4.8.

This paper presents a novel experimental protocol for the evaluation of the thermodynamic performance of working pairs for application in adsorption heat pumps and chillers. The proposed approach is based on the experimental measurements of the main thermo-physical parameters of adsorbent pairs, by means of a DSC/TG apparatus modified to work under saturated vapour conditions, able to measure the ads-/desorption isobars and heat flux as well as the adsorbent specific heat under real boundary conditions. Such kind of activity allows to characterize the thermodynamic performance of an adsorbent pair allowing the estimation of the thermal Coefficient Of Performance (COP) both for heating and cooling applications, only relying on experimental values. The experimental uncertainty of the method has been estimated to be around 2%, for the COP evaluation. In order to validate the proposed procedure, a first test campaign has been carried out on the commercial adsorbent material, AQSOA-Z02, produced by MPI (Mitsubishi Plastics Inc.), while water was used as refrigerant. The proposed experimental methodology will be applied on several other adsorbent materials, either already on the market or still under investigation, in order to get an easy and reliable method to compare thermodynamic performance of adsorptive working pairs.

The aim of this study was to evaluate the fatty acid composition, lipolysis, lipid oxidation and volatile organic compounds (VOCs) in Colonnata lard from Large White (LW) or Cinta Senese (CS) pigs during one-year curing. CS lard contained a higher amounts of unsaturated fatty acids than LW one, due to the different rearing and feeding systems. Despite the higher lipolysis in CS backfat during the curing period, the rate of fatty acid and cholesterol oxidation was higher in LW. The amount of cholesterol oxidation products (COPs) and thiobarbituric acid reactive substances (TBARs) significantly decreased after 3 months of curing, regardless of the type of lard. VOCs composition of lard was affected by curing time, but not by breed. While volatile fatty acid oxidation products (mainly aldehydes) were present at the beginning of the curing time, subsequently other volatiles compounds (such as sulphur compounds and terpenes) that derived from ingredients used for lard production, increased in lard samples.

IHX is probably, one of the most commonly alternative used to improve cooling capacity and COP in a CO2 refrigerating plant working in supercritical conditions. The classical position at gas-cooler exit has been analyzed by several authors with positive results. The aim of this work is to compare, from experimental approach, the energetic behavior of a refrigerating plant working with several IHX configurations: gascooler exit (classical position), liquid receiver exit, and in both positions at the same time. The energetic behavior includes: cooling capacity, power consumption and COP. Moreover, the discharge temperature reached on each position has been analyzed. From the experimental results, a general improvement in COP and cooling capacity has been observed regardless the position of the IHX. A maximum increment of 13% on COP has been registered working with two IHX at the same time., The authors are indebted to the Spanish Ministry of Education and Science (IESCO2) and to the Spanish Ministry of the Environment and Rural and Marine Affairs (ENE2011-22968) for the economic support given to the present work.

Objectives This paper aims to present a parametric study to compare with the experimental results obtained previously for a typical activated carbon–methanol, adsorption air-conditioning system powered by exhaust heat. The main objective is to study the effect of wall thickness on the desorption temperature and the cooling performance. Methods The current study is a simulation/parametric investigation employing computational fluid dynamics (CFD) simulation technique. Results It is found that the CFD result is close to the experimental works. In this CFD investigation, an input exhaust gas of 200 °C would have bed temperature around 120 °C while employing 20 mm thick of wall made by stainless steel. The adsorber took around 10 min to heat up and decrease to room temperature around the same period. This set of data produce a cooling power of 0.65 kW and COP around 0.25 with cycle time of 1200 s. Conclusion It is concluded that higher input temperature would have relatively longer cycle time but it is able to produce higher cooling power in return. While in design, it proves that an optimal wall thickness should be 15–20 mm of stainless steel that offer lower heat transfer rate to maintain the system under functional T des at all time. Practice implications This paper proves that adsorption air-conditioning system is technically applicable; however wall thickness of the adsorber should be considered seriously as one of the important parameters for suitable heat transfer and improved adsorption–desorption rate of the system.

In this study, we designed a multifunctional heat pump system using just one scroll compressor and which can be run in four different modes, namely air to air, air to water, water to water and water to air, in order to make an experimental energetic and exergetic performance comparison. Experimental system consists of two condensers and two evaporators and uses R22 as working fluid. One of the evaporators and condensers uses water and the others use air as heat source/sink. Heating capacities of four heat pump types are equal to each other. It is realized by adjusting the mass flow rate and temperature level of external fluid of condenser. Results show that the heat pump unit which has the maximum COP (coefficient of performance) value is water to air type with 3.94 and followed by water to water type with 3.73, air to air type with 3.54 and air to water type with 3.40. Ranking of four heat pump types with respect to their mean exergy efficiency is as follows; water to air type with 30.23%, air to air type with 30.22%, air to water type with 24.77% and water to water type with 24.01%. Exergy destruction rates of the systems were investigated in this study and the results revealed that the heat pump type which has the maximum exergy destruction is air to air type with 2.93 kW. The second highest one is air to water type with 2.84 kW. The third highest one is water to air type with 2.64 kW and last one is water to water type with 2.55 kW. It is understood that the temperature of the evaporator external fluid affects the exergetic efficiency of the system more than the mass flow rate. In contrast to the previous, the dominant parameter which has more important effect on the exergy destruction of the heat pump unit is the mass flow rate of evaporator external fluid. (C) 2013 Elsevier Ltd. All rights reserved.

The coefficient of performance, COP, of an adsorption cooling is theoretically obtained. It shows the influence of the thermophysical properties of the adsorbent-adsorbate media regardless of the design of the machine. These quantities require a detailed understanding of the influence of temperature on the adsorbent and the adsorbate conditions in a cycle, so that an accurate determination of the thermodynamic behaviour is developed in order to obtain the COP.

The aim of this paper is to present an easy instrument and method for postural balance analysis based on evaluation of instantaneous center of gravity (COG) were the subject is stand on innovative force platform. The instrument is realized with three identical composite sensor supporting a feet plate were used to measure the ground reaction force applied by subject during postural balance analysis. A Microsystems based on microcontroller was built in order to drive the instrumentation and a graphical user interface was realized. The signals acquisitions are displayed on the PC screen when the COG moves in the xy plan. After the calculation and programming of the COG coordinates point, the plot of the XG and YG time series of the COG position during a postural balance analysis is easily obtained and recording. The effect of visual input is studied by performing the test with eyes open and then closed. The dynamic parameters show clear indicator of the postural balance. Objective method of diagnosis is to access to postural stability for identifying persons at risk of falling.

In the present work a new configuration of absorption refrigeration machine based on phase separation has been studied. The main objective is to investigate the performance of this machine, using a number of binary systems (refrigerant absorbent) showing a partial miscibility and having a low critical solution temperature. A computer code has been developed for the calculation of the coefficient of performance ( COP ) of the machine as well as to study the influence of the operating conditions on this parameter, testing a binary mixture made of methyl diethyl amine ( MDEA ) as refrigerant and water as absorbent. The obtained results confirm the feasibility of this new cycle which can be regarded as a good alternative to classical cycle with no phase separation. The use of the computer code can be extended to test different working fluids for this machine, for an optimisation of the COP .

One of the main challenges of the industry today is to face its impact on global warming considering that the greenhouse effect problem is not be solved completely yet. Magnetic refrigeration represents an environment-safe refrigeration technology. The magnetic refrigeration is analysed using the second law analysis in order to obtain a model for engineering application.

The air cycle refrigeration system used in Chinese train air conditioning engineering is investigated. The effects of possible parameters affecting system performance are examined through sensitive analysis of the thermodynamic model. The results show that, the pressure ratio should be in the range of 2-2.5, the COP will be in the range of 1-1.2, and the cold air distribution system can be used. To increase the COP, higher efficiencies of compressors, expanders and heat exchangers are expected.

Heat pump systems can be found in high number of applications. One of these is the production of domestic hot water. This paper presents a quasi-steady state simulation model to predict the performance of a simple air source heat pump water heater (ASHPWH). The mathematical model consists of submodels of the basic system components, namely, evaporator, condenser, compressor, and expansion valve. These submodels were built based on fundamental principles of heat transfer and thermodynamics. The model was coded into MATLAB software and used to predict system parameters of interest such as hot water temperature, evaporating and condensing pressures, heat rejected in the condenser, electric power input, heating seasonal performance factor, and coefficient of performance.

This study deals with energy and irreversibility analysis of a cascade refrigeration system employing various refrigerant couples, namely R152a–R23, R290–R23, R507–R23, R234a–R23, R717–R23 and R404a–R23, using a computer code developed for this aim. It is assumed that the refrigeration load is 1 kW, the refrigerated space temperature is −40 °C, and the environment temperature is 300 K, while the degrees of condenser subcooling and evaporator superheat are 5 and 7 °C, respectively, for all cases. Furthermore, the polytropic efficiencies of the compressors are assumed to be equal. It has been determined that the COP of the cascade refrigeration system increases and the irreversibility decreases with rising evaporator temperature and polytropic efficiency for all studied refrigerant couples. On the other hand, the COP of the cascade refrigeration system decreases and the irreversibility increases on increasing the condenser temperature and the difference between the saturation temperatures of the lower and higher temperature systems in the heat exchanger (ΔT). In all cases, the refrigerant couple R717–R23 has the highest COP and lowest irreversibility except for the limited ranges of polytropic efficiency (50–60%) and ΔT (13 K–16 K), while R507–R23 has the lowest COP and highest irreversibility. The refrigerant couple R152a–R23 has been found to be an alternative couple to R717–R23 for the above mentioned ranges of polytropic efficiency and ΔT. The refrigerant couples R134a–R23 and R290–R23 have placed in the middle range, and R404a–R23 can be considered as a replacement couple for R507–R23 in all cases.

A cold generation system featuring a Rankine cycle powered refrigeration cycle actuated by a supersonic ejector was theoretically investigated in view of the thermo-fluid-dynamic optimization of the working fluid characteristics. The ejector model was validated against well established performance charts relating to water. A reference system was considered in which a Rankine cycle at moderate top temperature delivers its expansion power by means of an ideal turbine to an ideal compressor of a refrigeration cycle. Two main optimizing variables were ascertained: the fluid critical temperature and the complexity of the fluid molecule. The best performance of such reference cycle is around 80% of that of an ideal fully reversible, Carnot cycle based, system (COP of 2.0 for tE,PC = 150 °C, tE,RC = 5 °C, and tC = 35 °C). As easily predictable the ejector compression introduces severe losses mainly due to the normal shock and the mixing of the motive and of the driven fluid. Overall COP for the above quoted temperatures decreases from 2.0 (reference cycle) to 0.4–0.7. The optimization of the working fluid showed that comparatively low critical temperatures are favoured and that a fluid complexity similar to that of CH5N or CH2Cl2 gives the best performance. A detailed losses analysis explains this behaviour. In particular at low reduced temperatures the theoretical gain related to the better shape in the T–S plane of both the power and the refrigeration cycle is more than offset by the higher ejector losses due to the stronger normal shock needed to cope with an increased pressure ratio. Notwithstanding an extensive fluid screening we did not succeed in finding a fluid that could be considered optimum from all points of view including ambient and safety issues. However, a number of traditional (non-zero ODP) chloro-fluoro-carbons and of new (zero ODP) refrigerants were found that yield, on the whole, a satisfactory performance. Provided calculated COP will be confirmed by experimental testing, ejector powered refrigerators could compete with absorption systems in many applications.

International audience; An exergy-based analysis applied to ideal thermochemical dipoles allowed to design an original process that could use low-grade energy, produced from a thermal solar collector at around 70 °C, to provide low-temperature cold, below −23 °C, in order to store deep-frozen food. The ideal coefficient of performance (COP) of this system is 0.5 and the exergetic yield is 1. Taking into account the process enthalpies and the sensible heat of the reactants, the COPthermo is 0.17. The process functioning is described in this paper. It alternates between a regeneration mode during daytime and cold production mode during night-time. An experimental prototype was designed and built. It proved the feasibility of the concept and showed an experimental COP of about 0.06, which is similar to the up-to-date solar cooling systems, but at higher cold temperatures. The mean annual exergetic yield of the process is about 0.06.

A city-scale renewable energy network for heating and cooling can significantly contribute to reduction of fossil fuel utilization and meeting the renewable energy targets. Ground source heat pump (GSHP) system is a technology that transfers heat stored over long periods to/from the ground to heat/cool the buildings. In particular, a vertical closed loop GSHP is a viable choice in densely populated urban areas. In this study, an ArcGIS-based simulation model has been developed to examine how many vertical closed loop GSHPs can be feasibly installed at city scale without overusing the geothermal energy underground. City of Westminster, in London, is used as a case study to identify and map areas where GSHPs can serve as a viable option for heating and/or cooling. A parametric study has been conducted to investigate the influence of how space heating and cooling demand is quantified on the potential utility of GSHP systems. The influence of COP variation during operation is also examined. The operational variation of COP influences the electricity consumption of the GSHP systems. Therefore, a comprehensive analysis including the capital cost, C/D ratio distribution, energy demand, and financial risk is highly recommended for district-level planning of GSHP systems.

CARD only protein (Cop) was recently identified as a protein with significant homology with the CARD of caspase-1. We have conducted functional studies on Cop and report on its role as an inhibitor of cell death in a broad range of cell death paradigms. A notable exception in the ability of Cop to inhibit cell death pertains to its inability to inhibit ER stress-mediated cell death. Furthermore, in addition to the known interaction of Cop and caspase-1, we demonstrated a novel interaction of Cop with caspase-4. We propose that Cop's action to prevent TNF-α-induced cell death may operate independently of the mitochondrial death pathway. Furthermore, Cop overexpression inhibits Bid cleavage. In summary, Cop inhibition of cell death, at least to a certain extent, results from its interference with the activation of caspase-1 and caspase-4. Understanding the mechanistic details modulating caspase cell death pathways should provide important information for the development of therapies for diseases featuring aberrant caspase activation. Cop, as an inhibitor of an important apical caspase cell death axis, may provide a tool for modulating pathological cell death.

Various field-test systems using carbon dioxide as the only refrigerant have been installed since December 2001. In this paper we will analyse an ‘all-CO2’ supermarket, which has been operating in the North of Italy since January 2003. The seasonal COP is calculated, based on prior laboratory measurements, and a comparison is made with a conventional direct expansion system using R404A. The total annual energy consumption of the installed CO2 system is estimated to be about 10% higher than the direct expansion R404A solution. It is still possible to further improve efficiency and approach the efficiency of present R404A systems. These improvements are identified. The cost of the CO2 installation is compared to the cost of an equivalent direct expansion R404A installation, the most economic among the various present types of commercial refrigeration systems. Because of the lack of suitable mass-produced components, the CO2 installation is estimated to be, today, about 20% more expensive.

A comparative study between traditional patés elaborated with pork liver and fish patés (salmon, anchovy and cod) was carried out. The nutritional value and their security related to cholesterol oxidation products (COP) content were evaluated. Salmon paté showed similar fat content (24-28%) and energetic value (300Kcal/100g) to pork liver patés, whereas patés made with anchovy and cod showed less fat (13-16%) and calories (200-236 Kcal/100g). PUFA/SFA ratios were much higher in all fish patés (1.55-4.95) than in liver pork patés (0.36-0.44). No great differences were found in ω-6/ω-3 ratio between salmon and pork liver patés (11.34-18.4), being even much higher this ratio in anchovy (32.32) and cod patés (62.77). EPA and DHA supply was around 0.63 for salmon, 0.21 for anchovy and 0.07 for cod patés. Cholesterol amounts were lower in fish patés (31-37mg/100g) than in pork liver patés (77-102mg/100g). Total COP ranged 0.38-2.83ppm, without clear differences between pork liver and fish patés.

A device for the dissipation the heat from the hot side of Peltier pellets in thermoelectric refrigeration, based on the principle of a thermosyphon with phase change is presented. The device design was accomplished by analytic calculations on the base of a semi-empirical formulation and simulations with computational fluids dynamics. In the experimental optimization phase, a prototype of thermosyphon with a thermal resistance of 0.110 K/W has been development, dissipating the heat of a Peltier pellet with the size of 40 × 40 mm, what is an improvement of 36% in the thermal resistance, with regard to the commercial fin dissipater. With the construction of the two prototypes of thermoelectric domestic refrigerators, one of them with the device developed, and the other with a conventional fins dissipater, it could be experimentally proved that the use of thermosyphon with phase change increases the coefficient of performance up to 32%. © 2003 Elsevier Ltd. All rights reserved.

Contextualising on the internationally low oil prices era and historically high oil production in USA and refusal to honour the commitments under Paris Agreement (COP: 21), this study investigates the role of education, oil prices and natural resources on energy demand and CO2 emissions in the USA for the period of 1976-2016. In so doing, we employed a bounds testing approach to cointegration accounting for structural breaks in the series. Key findings suggest the presence of a long-run association between underlying variables. The abundance of natural resources and economic growth of the US economy seem to weigh on environmental quality by increasing energy consumption and carbon emissions. Oil prices show a negative association with energy consumption as well as carbon emissions suggesting that a low oil prices regime can lead to an increase in carbon emissions and energy consumption. Interestingly, education seems to play an important role by reducing energy consumption and carbon emissions, resultantly improving the US environmental quality. Our findings have profound environmental implications in terms of efforts to tackle climate change and meeting the Paris agreement (COP: 21) ambitions with reality and USA policy stance.