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The paper is related to the use of magnetic nanofluids (ferrofluids) in a direct absorption solar parabolic trough collectors enhances thermal efficiency compared to conventional solar collectors. By applying the right magnetic intensity and magnetic field direction, the thermal conductivity of the fluid increased higher than typical nanofluids. Moreover, the ferrofluids exhibit excellent optical properties. The external magnetic source is installed to alter the thermos-physical properties of the fluid, and the absorber tube does not have selective surface allowing ferrofluids to absorb the incoming solar irradiance directly. In this paper, an experimental investigation of the performance of direct absorption solar collector using ferrofluids as an absorber. Various nanoparticle concentrations 0% to 1vol% at the operational temperatures between 19°C and 40°C were used in the current study. The results show that using ferrofluids as a heat transfer fluid increases the efficiency of solar collectors. In the presence of the external magnetic field, the solar collector efficiency increases to the maximum, 25% higher than the conventional parabolic trough. At higher temperatures, the ferrofluids show much better efficiency than conventional heat transfer fluid. The study indicated that nanofluids, even of low-content, have good absorption of solar radiation, and can improve the outlet temperatures and system efficiencies.

Evaporative cooling has been considered a low energy consumption process that often is associated with displacement ventilation and passive cooling strategies of buildings. While significant energy savings can be accrued from using evaporative cooling, there are many design challenges to improve the processes of heat and mass transfer and reduce design complexities. This paper seeks to advance the design of evaporative cooling through building and testing a novel regenerative evaporative cooler prototype. It proposes a design that integrates heat pipe and porous ceramic tube modules as an alternative to plate heat exchangers. The paper describes design arrangement of the cooler, a mathematical model and laboratory test results. Under controlled laboratory test conditions, the measured performance indices of wet bulb effectiveness, specific cooling capacity and coefficient of performance (COP) were determined as 0.8, 140 W per m2 of wet ceramic surface area and 11.43 respectively. Furthermore, experimental results show that under typical ambient conditions commensurate with that prevailing in arid climates, the cooler air supply temperature was as much as 14 oC below that of the ambient air.

This paper presents results of a research study into improving energy performance of small-scale district heat network through water supply and return temperature optimization technique. The case study involves establishing the baseline heat demand of the estate’s buildings, benchmarking the existing heat network operating parameters, and defining the optimum supply and return temperature. A stepwise temperature optimization technique of plate radiators heat emitters was applied to control the buildings indoor thermal comfort using night set back temperature strategy of 21/18 °C. It was established that the heat network return temperature could be lowered from the current measured average of 55 °C to 35.6 °C, resulting in overall reduction of heat distribution losses and fuel consumption of 10% and 9% respectively. Hence, the study demonstrates the potential of operating existing heat networks at optimum performance and achieving lower return temperature. It was also pointed out that optimal operation of future low temperature district heat networks will require close engagement between the operator and the end user through incentives of mutual benefit.

Project SCENIC (Smart Controlled Energy Networks Integrated in Communities) involves connecting properties at the University of Nottingham’s Creative Energy Homes test site in a community scale, integrated heat and power network. Controls will be developed to allow for the most effective heat load allocation and power distribution scenarios. Furthermore, the system will develop the prosumer concept, where consumers are both buyers and sellers of energy in both heat and power systems. This paper describes the initial phase of project SCENIC, achieving truly distributed generation within a heat network. The first of its kind, the system has a four pipe network configuration, consisting of a network flow loop to supply heat to homes, and a generation loop to collect energy from residential heating systems and supply it to a centralised thermal store. To achieve the design, IES-VE steady state heat load and dynamic building modelling have been used. A pre-insulated Rehau Rauthermex piping diameter was sized using flow rate calculations. Pipe diameter is reduced in line with distance from the central pump and associated pressure losses. The diameter ranges from 40 to 25mm, with a heat loss as low as 7.0 W/m. In addition, flow rates will fluctuate below a maximum of 1.99 l/s. Danfoss – 7 Series BS flatstations have been selected as the network-building heat interface units (HIU), to satisfy a calculated peak design heating loads of between 36.74 and 44.06 kW. Furthermore, to enable the prosumer concept and associated business models an adapted Danfoss Flatstations – 3 Series BS was selected to interface the distributed heat sources with the network. This paper gives details of the novel system configuration and concept, energy flows, as well as calculation and modelling results for the heat network. A premise is given to maintaining low temperatures in the network to ensure system efficiency in line with the latest research thinking.

The paper presents computer modelling and laboratory experiment results of a sub-wet bulb temperature indirect evaporative cooling system for space cooling in buildings. The prototype employs hollow porous ceramic water containers as wet media material for water evaporation. The cooled air is delivered without increasing its moisture content. The performance of the cooler was evaluated using a computer model, and the results of which were validated experimentally. The cooling capacity and effectiveness of the cooler were evaluated at inlet air dry bulb temperature of 30 and 35°C and relative humidity ranging from 35% to 50%. It was found that the cooler can supply air for space cooling at sub-wet bulb temperature conditions; achieve measured cooling capacity approaching 225 W/m2 of exposed ceramic material wet surface area and wet bulb effectiveness higher than unity. The high thermal performance of the constructed evaporative cooler indicates the system could be a potential substitute to conventional mechanical air-conditioning systems in buildings in many parts of the world where hot and dry climatic conditions prevail.

This study presents a method to adapt existing hydronic systems in buildings to take advantage of low temperature district heating (LTDH). Plate radiators connected to double string heating circuits were considered in an optimization procedure, based on supply and return temperatures, to obtain the required logarithmic mean temperature difference (LMTD) for a low temperature heating system. The results of the analysis are presented as the average reduction of LMTD over the heating season compared to the base case design conditions. Two scenarios were investigated based on the assumption of a likely cost reduction in the end users' energy bills of 1% for each 1 °C reduction of return and average supply and return temperatures. The results showed possible discounts of 14% and 16% respectively, due to more efficient operation of the radiators. These were achieved without any intervention in the thermal envelope or to the heating systems, through simply adjusting the temperatures according to demand and properly controlling the plate radiators with thermostatic radiator valves (TRVs).

Numerous FPSE designs have been demonstrated, tested and maybe commercially produced for different applications since Beale had invented the first design of the FPSE. The proposed design of FPSE is intended to operate at atmosphere pressure and low heat source temperature for power generation applications. The proposed design aims to address some of the disadvantages associated to the FPSEs, such as seal leakage, hysteresis losses and side forces, with the considerations of the mechanism and assembly to be simple and straightforward. The focus was on the components and the design of the displacer and the power piston as they are of the main parts in the FPSE influence its operation and performance. The displacer and the power piston have improved by integrating sorts of flexible materials that being used in replace of the typical mechanical springs. The flexible metal component used in replace of the conventional mechanical springs has the properties of elasticity, rigidity, low density and low thermal conductivity beside its cylindrical housing shape. A prototype for the novel configuration with the integration of stainless bellows and rubber diaphragm is built to be work at low and medium temperature range. The engine is gradually improved so that the objectives of the configuration are achieved. The FPSE prototype is demonstrated and tested in the lab to assure that the new configuration is working properly. The engine is new in terms of design mechanical configuration; however, it showed aspiring results.

The paper presents design and preliminary testing results of a Free Piston Stirling Engine (FPSE) prototyp operating at low temperature heat sources. The main focus of this work is to demonstrate the construction of the displacer using flexure bellows as a mechanical supporting spring and as a working fluid seal. The power piston, on the other hand, is made of a planar elastomer material in the shape of a disk with a suitable mechanical elasticity, rigidity, and thermal properties to support the range of operating temperatures. A small prototype of the FPSE was built and tested at operating temperature of under 200 oC. The measured operating frequency was 15 Hz, a reciprocating stroke of 8mm and operating pressure close to atmospheric pressure. The prototype was equipped with instruments to measure all the operating parameters. The power output was measured from the p-v diagram using a two-channel oscilloscope. The preliminary results demonstrated the operation concept and reliable start up, but further improvements will be needed to fine tune the reciprocating components and reduce mechanical friction.

The paper presents laboratory test results of an integrated heat pipe and ceramic tube based evaporative cooling prototype for air conditioning in buildings. The cooler integrates durable porous ceramic tubes as water saturated media materials and heat pipes as efficient heat transfer devices. The ceramic tubes and the heat pipes straddle across two separate air ducts to form a wet and dry channel respectively. The thermal performance of the cooler was measured at various air inlet conditions of temperature, humidity and mass flow rates. The experimental measurements show that the cooling system can provide sufficient cooling as high as 1220 W/m2 of the wet media exposed surface area and depressing ambient temperature to 12℃. Equally, it was measured that the wet bulb effectiveness of the cooler can reach 86%.

This paper presents the results of a CFD analysis and experimental tests of two identical miniature flat plate heat pipes (FPHP) using sintered and screenmesh wicks and a comparative analysis and measurement of two solid copper base plates 1mmand 3mmthick. It was shown that the design of the miniature FPHP with sintered wick would achieve the specific temperature gradients threshold for heat dissipation rates of up to 80W.The experimental results also revealed that for localised heat sources of up to 40W, a solid copper base plate 3mm thick would have comparable heat transfer performances to that of the sintered wick FPHP. In addition, a marginal effect on the thermal performance of the sintered wick FPHP was recorded when its orientation was held at 0∘, 90∘, and 180∘ and for heat dissipation rates ranging from 0 to 100W.

The paper is related to the use of magnetic nanofluids (ferrofluids) in a direct absorption solar parabolic trough collectors enhances thermal efficiency compared to conventional solar collectors. By applying the right magnetic intensity and magnetic field direction, the thermal conductivity of the fluid increased higher than typical nanofluids. Moreover, the ferrofluids exhibit excellent optical properties. The external magnetic source is installed to alter the thermos-physical properties of the fluid, and the absorber tube does not have selective surface allowing ferrofluids to absorb the incoming solar irradiance directly. In this paper, an experimental investigation of the performance of direct absorption solar collector using ferrofluids as an absorber. Various nanoparticle concentrations 0% to 1vol% at the operational temperatures between 19°C and 40°C were used in the current study. The results show that using ferrofluids as a heat transfer fluid increases the efficiency of solar collectors. In the presence of the external magnetic field, the solar collector efficiency increases to the maximum, 25% higher than the conventional parabolic trough. At higher temperatures, the ferrofluids show much better efficiency than conventional heat transfer fluid. The study indicated that nanofluids, even of low-content, have good absorption of solar radiation, and can improve the outlet temperatures and system efficiencies.

This paper describes a multi-energy system optimisation software, “Sustainable Energy Management System” (SEMS), developed as part of a Siemens, Greater London Authority and Royal Borough of Greenwich partnership in collaboration with the University of Nottingham, Nottingham Trent University and Imperial College London. The software was developed for application at a social housing estate in Greenwich, London, as part of the Borough’s efforts to retrofit the energy systems and building fabric of its housing stock. Its purpose is to balance energy across vectors and networks through day-ahead forecasting and optimisations that can be interpreted as control outputs for energy plant such as a water source heat pump, district heating pumps and values, power switchgear, gas boilers, a thermal store, electric vehicle chargers and a photovoltaic array. The optimisation objectives are to minimise greenhouse gas emissions and operational cost. The tool uses Hypernetwork Theory based orchestration coupled with a microservice architecture. The distributed nature of the design ensures flexibility and scalability. Currently, microservices have been programmed to forecast domestic heating demand, domestic electricity demand, electric vehicle demand, solar photovoltaic generation, ground temperature, and to run a day-ahead energy balance optimisation. This paper presents the results from both domestic heat and electricity demand forecasting, as well as the overall design and integration of the software with a physical system. The works build on that of O’Dwyer, et al. (2020) who developed a preliminary energy management software and digital twin. Their work acts as a foundation for this real-world commercialisation-ready program that integrates with physical assets.

This paper presents results of a research study into improving energy performance of small-scale district heat network through water supply and return temperature optimization technique. The case study involves establishing the baseline heat demand of the estate’s buildings, benchmarking the existing heat network operating parameters, and defining the optimum supply and return temperature. A stepwise temperature optimization technique of plate radiators heat emitters was applied to control the buildings indoor thermal comfort using night set back temperature strategy of 21/18 °C. It was established that the heat network return temperature could be lowered from the current measured average of 55 °C to 35.6 °C, resulting in overall reduction of heat distribution losses and fuel consumption of 10% and 9% respectively. Hence, the study demonstrates the potential of operating existing heat networks at optimum performance and achieving lower return temperature. It was also pointed out that optimal operation of future low temperature district heat networks will require close engagement between the operator and the end user through incentives of mutual benefit.

Project SCENIC (Smart Controlled Energy Networks Integrated in Communities) involves connecting properties at the University of Nottingham’s Creative Energy Homes test site in a community scale, integrated heat and power network. Controls will be developed to allow for the most effective heat load allocation and power distribution scenarios. Furthermore, the system will develop the prosumer concept, where consumers are both buyers and sellers of energy in both heat and power systems. This paper describes the initial phase of project SCENIC, achieving truly distributed generation within a heat network. The first of its kind, the system has a four pipe network configuration, consisting of a network flow loop to supply heat to homes, and a generation loop to collect energy from residential heating systems and supply it to a centralised thermal store. To achieve the design, IES-VE steady state heat load and dynamic building modelling have been used. A pre-insulated Rehau Rauthermex piping diameter was sized using flow rate calculations. Pipe diameter is reduced in line with distance from the central pump and associated pressure losses. The diameter ranges from 40 to 25mm, with a heat loss as low as 7.0 W/m. In addition, flow rates will fluctuate below a maximum of 1.99 l/s. Danfoss – 7 Series BS flatstations have been selected as the network-building heat interface units (HIU), to satisfy a calculated peak design heating loads of between 36.74 and 44.06 kW. Furthermore, to enable the prosumer concept and associated business models an adapted Danfoss Flatstations – 3 Series BS was selected to interface the distributed heat sources with the network. This paper gives details of the novel system configuration and concept, energy flows, as well as calculation and modelling results for the heat network. A premise is given to maintaining low temperatures in the network to ensure system efficiency in line with the latest research thinking.

The paper presents computer modelling and laboratory experiment results of a sub-wet bulb temperature indirect evaporative cooling system for space cooling in buildings. The prototype employs hollow porous ceramic water containers as wet media material for water evaporation. The cooled air is delivered without increasing its moisture content. The performance of the cooler was evaluated using a computer model, and the results of which were validated experimentally. The cooling capacity and effectiveness of the cooler were evaluated at inlet air dry bulb temperature of 30 and 35°C and relative humidity ranging from 35% to 50%. It was found that the cooler can supply air for space cooling at sub-wet bulb temperature conditions; achieve measured cooling capacity approaching 225 W/m2 of exposed ceramic material wet surface area and wet bulb effectiveness higher than unity. The high thermal performance of the constructed evaporative cooler indicates the system could be a potential substitute to conventional mechanical air-conditioning systems in buildings in many parts of the world where hot and dry climatic conditions prevail.

Numerous FPSE designs have been demonstrated, tested and maybe commercially produced for different applications since Beale had invented the first design of the FPSE. The proposed design of FPSE is intended to operate at atmosphere pressure and low heat source temperature for power generation applications. The proposed design aims to address some of the disadvantages associated to the FPSEs, such as seal leakage, hysteresis losses and side forces, with the considerations of the mechanism and assembly to be simple and straightforward. The focus was on the components and the design of the displacer and the power piston as they are of the main parts in the FPSE influence its operation and performance. The displacer and the power piston have improved by integrating sorts of flexible materials that being used in replace of the typical mechanical springs. The flexible metal component used in replace of the conventional mechanical springs has the properties of elasticity, rigidity, low density and low thermal conductivity beside its cylindrical housing shape. A prototype for the novel configuration with the integration of stainless bellows and rubber diaphragm is built to be work at low and medium temperature range. The engine is gradually improved so that the objectives of the configuration are achieved. The FPSE prototype is demonstrated and tested in the lab to assure that the new configuration is working properly. The engine is new in terms of design mechanical configuration; however, it showed aspiring results.

This study presents a method to adapt existing hydronic systems in buildings to take advantage of low temperature district heating (LTDH). Plate radiators connected to double string heating circuits were considered in an optimization procedure, based on supply and return temperatures, to obtain the required logarithmic mean temperature difference (LMTD) for a low temperature heating system. The results of the analysis are presented as the average reduction of LMTD over the heating season compared to the base case design conditions. Two scenarios were investigated based on the assumption of a likely cost reduction in the end users' energy bills of 1% for each 1 °C reduction of return and average supply and return temperatures. The results showed possible discounts of 14% and 16% respectively, due to more efficient operation of the radiators. These were achieved without any intervention in the thermal envelope or to the heating systems, through simply adjusting the temperatures according to demand and properly controlling the plate radiators with thermostatic radiator valves (TRVs).

The paper presents design and preliminary testing results of a Free Piston Stirling Engine (FPSE) prototyp operating at low temperature heat sources. The main focus of this work is to demonstrate the construction of the displacer using flexure bellows as a mechanical supporting spring and as a working fluid seal. The power piston, on the other hand, is made of a planar elastomer material in the shape of a disk with a suitable mechanical elasticity, rigidity, and thermal properties to support the range of operating temperatures. A small prototype of the FPSE was built and tested at operating temperature of under 200 oC. The measured operating frequency was 15 Hz, a reciprocating stroke of 8mm and operating pressure close to atmospheric pressure. The prototype was equipped with instruments to measure all the operating parameters. The power output was measured from the p-v diagram using a two-channel oscilloscope. The preliminary results demonstrated the operation concept and reliable start up, but further improvements will be needed to fine tune the reciprocating components and reduce mechanical friction.

The paper presents laboratory test results of an integrated heat pipe and ceramic tube based evaporative cooling prototype for air conditioning in buildings. The cooler integrates durable porous ceramic tubes as water saturated media materials and heat pipes as efficient heat transfer devices. The ceramic tubes and the heat pipes straddle across two separate air ducts to form a wet and dry channel respectively. The thermal performance of the cooler was measured at various air inlet conditions of temperature, humidity and mass flow rates. The experimental measurements show that the cooling system can provide sufficient cooling as high as 1220 W/m2 of the wet media exposed surface area and depressing ambient temperature to 12℃. Equally, it was measured that the wet bulb effectiveness of the cooler can reach 86%.

This paper presents the results of a CFD analysis and experimental tests of two identical miniature flat plate heat pipes (FPHP) using sintered and screenmesh wicks and a comparative analysis and measurement of two solid copper base plates 1mmand 3mmthick. It was shown that the design of the miniature FPHP with sintered wick would achieve the specific temperature gradients threshold for heat dissipation rates of up to 80W.The experimental results also revealed that for localised heat sources of up to 40W, a solid copper base plate 3mm thick would have comparable heat transfer performances to that of the sintered wick FPHP. In addition, a marginal effect on the thermal performance of the sintered wick FPHP was recorded when its orientation was held at 0∘, 90∘, and 180∘ and for heat dissipation rates ranging from 0 to 100W.

This paper presents results of a research study into improving energy performance of small-scale district heat network through water supply and return temperature optimization technique. The case study involves establishing the baseline heat demand of the estate’s buildings, benchmarking the existing heat network operating parameters, and defining the optimum supply and return temperature. A stepwise temperature optimization technique of plate radiators heat emitters was applied to control the buildings indoor thermal comfort using night set back temperature strategy of 21/18 °C. It was established that the heat network return temperature could be lowered from the current measured average of 55 °C to 35.6 °C, resulting in overall reduction of heat distribution losses and fuel consumption of 10% and 9% respectively. Hence, the study demonstrates the potential of operating existing heat networks at optimum performance and achieving lower return temperature. It was also pointed out that optimal operation of future low temperature district heat networks will require close engagement between the operator and the end user through incentives of mutual benefit.

Project SCENIC (Smart Controlled Energy Networks Integrated in Communities) involves connecting properties at the University of Nottingham’s Creative Energy Homes test site in a community scale, integrated heat and power network. Controls will be developed to allow for the most effective heat load allocation and power distribution scenarios. Furthermore, the system will develop the prosumer concept, where consumers are both buyers and sellers of energy in both heat and power systems. This paper describes the initial phase of project SCENIC, achieving truly distributed generation within a heat network. The first of its kind, the system has a four pipe network configuration, consisting of a network flow loop to supply heat to homes, and a generation loop to collect energy from residential heating systems and supply it to a centralised thermal store. To achieve the design, IES-VE steady state heat load and dynamic building modelling have been used. A pre-insulated Rehau Rauthermex piping diameter was sized using flow rate calculations. Pipe diameter is reduced in line with distance from the central pump and associated pressure losses. The diameter ranges from 40 to 25mm, with a heat loss as low as 7.0 W/m. In addition, flow rates will fluctuate below a maximum of 1.99 l/s. Danfoss – 7 Series BS flatstations have been selected as the network-building heat interface units (HIU), to satisfy a calculated peak design heating loads of between 36.74 and 44.06 kW. Furthermore, to enable the prosumer concept and associated business models an adapted Danfoss Flatstations – 3 Series BS was selected to interface the distributed heat sources with the network. This paper gives details of the novel system configuration and concept, energy flows, as well as calculation and modelling results for the heat network. A premise is given to maintaining low temperatures in the network to ensure system efficiency in line with the latest research thinking.

The paper presents computer modelling and laboratory experiment results of a sub-wet bulb temperature indirect evaporative cooling system for space cooling in buildings. The prototype employs hollow porous ceramic water containers as wet media material for water evaporation. The cooled air is delivered without increasing its moisture content. The performance of the cooler was evaluated using a computer model, and the results of which were validated experimentally. The cooling capacity and effectiveness of the cooler were evaluated at inlet air dry bulb temperature of 30 and 35°C and relative humidity ranging from 35% to 50%. It was found that the cooler can supply air for space cooling at sub-wet bulb temperature conditions; achieve measured cooling capacity approaching 225 W/m2 of exposed ceramic material wet surface area and wet bulb effectiveness higher than unity. The high thermal performance of the constructed evaporative cooler indicates the system could be a potential substitute to conventional mechanical air-conditioning systems in buildings in many parts of the world where hot and dry climatic conditions prevail.