Investigation of a novel solar assisted heat recovery heat pump system for building space heating and hot water supply

With the rapid increment of energy consumption worldwide, the caused environmental contamination and global warming desperately necessitate the further development of renewable energy technologies. This study aims at presenting an in-depth investigation of a novel solar-assisted heat recovery heat pump (SAHR-HP) system for heating, cooling and domestic hot water (DHW) supply to resolve some barriers of the existing solar-assisted heat pump (SAHP) technologies, which include (1) performance reduction on the rear collectors of a solar collectors array; (2) poor performance at low ambient temperature; (3) long responding time due to the huge volume of the heat storage and exchange unit (HSEU); and (4) weak of strong complementarity between solar collector and heat pump. According to the barriers, the novel SAHR-HP system incorporates (1) a new designed mini-channel solar thermal collector with three inlets and outlets that can be connected with other solar collectors flexibly; (2) a solar collectors array with a novel multiple-throughout-flow connection method that can simultaneously increase the overall solar thermal efficiency and reduce the flowing resistance; (2) a novel vapour injection heat recovery air source heat pump (VIHRASHP) that can use both the exhausted air and the ambient air, thus leading a considerable performance increase of the heat pump in cold weather; (3) a novel fastresponding double-layered HSEU that can significantly shorten the response time.The study combined theoretical analysis and experimental and simulative investigation, including the following elements; a critical literature review, optimal preliminary design, theoretical analysis, the development of simulation models, prototype construction, laboratory-controlled and field testing, validation and performance optimisation of the simulation models, energy performance, economic performance and environmental influence analysis. The proposed SAHR-HP system has a COP from 3 to 8 according to the weather conditions. The multiple-throughout-flowing connection can improve solar thermal efficiency of a solar collectors array by 10% when compared with that of the conventional one-to-one connection. The novel HSEU can decrease the responding time to 20mins compared with the 3 hours of the conventional HSEU with the same heat storage volume. Particularly, the VIHR-ASHP can save about 23% of electricity consumption as compared with a conventional ASHP at normal operation conditions of condensation temperature of 45°C and an ambient temperature of -10°C. A lower ambient temperature will increase its advantages over conventional air source heat pump and vapor injection heat pump. The integral test results indicated that the SAHRHP system can perform in perfect union with the coordinative operation between different parts of the system under any environmental conditions. The energy performance and the economic and environmental analysis illustrated that this system could efficiently provide enough energy for space heating, cooling and DHW with high energy performance in cold climatic regions, such as Chongqing, Taiyuan and Urumqi. Compared with the coal-driven system, the novel system has a cost payback period of 13.8 years, 12.37 years, and 17.85 years in Chongqing, Taiyuan, and Urumqi and a life- cycle net cost saving of nearly 16145.84RMB, 20317.82RMB, and 9002RMB. Furthermore, the system reduces the emission of many other harmful substances, i.e., dust, SO2 and NOx, and is therefore a desirable approach for environment sustainability and clean air. Besides, the results can be extended to most cold areas worldwide, i.e., The UK and the European countries.The research results are expected to configure feasible solutions for future SAHP technologies. The wide promotion of these core technologies worldwide could significantly reduce the consumption of fossil fuel and the associated carbon footprint in a built-up environment, thus providing a more ecological environment

Assessment on the Efficiency of an Active Solar Thermal Facade: Study of the Effect of Dynamic Parameters and Experimental Analysis When Coupled/Uncoupled to a Heat Pump

The building sector presents poor performance in terms of energy efficiency and is looking for effective alternatives aimed at reducing the use of fossil fuels. The facade is a key element able to harness renewable energy as an Active Solar Thermal Facade (ASTF). The main purpose of this study is the assessment of a novel design concept based on a steel sandwich panel technology. The performance of the active system will be first addressed by a parametric study in order to analyze its behavior and secondly, by describing a real case based on an experimental test by connecting the active panels to a heat pump. The study shows the impact of solar irradiation and mass flow on the thermal jump achieved, while ambient and fluid inlet temperatures are the most influencing parameters in the efficiency of the facade. When coupled to the heat pump, results from a measurement campaign demonstrate a remarkable improvement in the performance of the ASTF. The results presented provide significant proof about the benefits of a synergetic combination of both technologies—solar facades and heat pumps—as efficient alternatives for the building sector, aiming to improve energy efficiency as well as reduce their dependence on non-renewable sources.This research was partially funded by the Basque Government through IT781-13 and IT1314-19 research groups and by the University of the Basque Country UPV/EHU through PES17/25. Additionally, TECNALIA Research & Innovation supported the research activities research through a cooperation agreement (PT10516) with UPV/EHU

Review of the advances in solar-assisted air source heat pumps for the domestic sector

Solar assisted air source heat pump shows great potential as a promising energy-saving heating technology, which integrates solar collector and air source heat pump. It is widely considered for supplying hot water, space heating and/or space cooling in the domestic sector. The performance of solar assisted air source heat pumps can be evaluated in system level by parameters such as coefficient of performance, seasonal performance factor, energy consumption, solar fraction as well as initial and operating costs, and in component level by parameters such as efficiencies of solar collection and thermal energy storage. Their performances are affected by many factors such as system configuration, components size, working fluid, working conditions and weather conditions. This paper presents a comprehensive review on the recent advances in solar assisted air source heat pump for the domestic sector in terms of system configuration, solar collectors, thermal energy storage, defrosting method and the perspective areas of further investigations. The results of this review confirm that research is still required to improve the performance of such a combined system and reduce initial cost compared with existing heating systems based on hydrocarbon combustion. The information presented in this paper is beneficial to the researchers, small and medium-sized enterprises supplying renewable energy system technologies, heating engineers and service workers, energy policy and decision makers, environmental activists and communities

Thermal Solar Energy Systems for Space Heating of Buildings

In this study, the simulation and the analysis of a solar flat plate collectors combined with a compression heat pump is carried out. The system suggested must ensure the heating of a building without the recourse to an auxiliary energy source in complement of this heating system. The system is used to heat a building using heating floor. The building considered is located in Constantine-East of Algeria (Latitude 36.28 N, Longitude 6.62 E, Altitude 689m). For the calculation, the month of February was chosen, which is considered as the coldest month according to the weather data of Constantine. The performances of this system were compared to the performances of the traditional solar heating system using solar collectors and an auxiliary heating load to compensate the deficit. In this case a traditional solar heating system having the same characteristics with regard to the solar collecting area and the volume of storage tank is used. It can be concluded that the space heating system using a solar energy combined with heat pump improve the thermal performance of the heat pump and the global system. The performances of the heating system combining heat pump and solar collectors are higher than that of solar heating system with solar collectors and storage tank. The heat pump assisted by solar energy can contribute to the conservation of conventional energy and can be competitive with the traditional systems of heating

Heat Pumps and Their Role in Decarbonising Heating Sector: A Comprehensive Review. ESRI WP627, June 2019

Addressing the growing concerns of climate change necessitates the decarbonisation of energy sectors globally. The heating sector is the largest energy end-use, accounting for almost half of the total energy consumption in most countries. This paper presents an extensive review of previous works on several aspects of heat pumps, including their role in the decarbonisation of the heating sector. In addition, we cover themes related to the recent technological advances of heat pumps as well as their roles in terms of adding flexibility to renewable-rich systems and carbon abatement. We also identify challenges and barriers for a significant uptake of heat pumps in various markets. Generally, as the share of renewables in the energy mix increases, heat pumps can play a role in addressing a multitude of problems induced by climate change. However, economic, regulatory, structural and infrastructural barriers exist, which may hinder heat pump integration rate

Monitoring and transient modelling of Solar assisted heat pump with hybrid Panels: limits and potentials applied to an existing plant

The Solar Assisted Heat Pumps represent one of the most interesting examples in the field of heating systems based on the interface of different generators. The present work provides a general overview about the topic of the solar assisted heat pumps, with specific attention to the current limits and potentials. Then, the pilot plant at Palacus is presented: a solar assisted heat pump is interfaced with hybrid panels and it represents the missing link between laboratory prototypes and full scale working plants. The most interesting part of the plant and its core is represented by the data acquisition system which allows an almost automatic control of the plant and a continuous collection of the over 50 measured working parameters of the facility. Indeed, this extended database will be used to validate a numerical transient model developed in TRNSYS environment. Thanks to this model, different optimisation analyses will be carried out, to increase the plant efficiency. In particular the following topics will be enquired: insulation of the connection pipes between the heat pump and the solar field and strategies to exploit the SAHP-PVT from both the thermal and photovoltaic point of view. In addition, the plant will be simulated at five different locations over Italy representing the main climatic zones, to carry out a preliminary simplified assessment tool to predict the SAHP performance according to the degree days of the installation site

Efficiency improvement of a ground coupled heat pump system from energy management

The installed capacity of an air conditioning system is usually higher than the average cooling or heating demand along the year. So, most of the time, the system is working under its actual capacity. In this contribution, we study the way to improve the efficiency of a ground coupled heat pump air conditioning system by adapting its produced thermal energy to the actual thermal demand. For this purpose, an air conditioning system composed by a ground coupled heat pump and a central fan coil linked to an office located in a cooling dominated area was simulated, and a new management strategy aiming to diminish electrical consumption was developed under the basic constraint that comfort requirements are kept. This strategy takes advantage of the possibility of managing the air flow in the fan, the water mass flows in the internal and external hydraulic systems, and the set point temperature in the heat pump to achieve this objective. The electrical consumption of the system is calculated for the new management strategy and compared with the results obtained for a conventional one, resulting in estimated energy savings around 30%This work has been supported by the Spanish Government under projects "Modelado y simulacion de sistemas energeticos complejos" (2005 Ramon y Cajal program), "Modelado, simulacion y validacion experimental de la transferencia de calor en el entorno de la edificacion" (ENE2008-0059/CON). A. Sala is grateful to the financial support of grants DPI2008-06731-c02-01 (Spanish Government), and Generalitat Valenciana Prometeo/2008/088.Pardo García, N.; Montero Reguera, ÁE.; Sala Piqueras, A.; Martos Torres, J.; Urchueguía Schölzel, JF. (2011). Efficiency improvement of a ground coupled heat pump system from energy management. Applied Thermal Engineering. 31(2):391-398. https://doi.org/10.1016/j.applthermaleng.2010.09.016S39139831

Modelling and Experimental Characterization of Photovoltaic/Thermal Systems for Cooling and Heating of Buildings in different climate conditions

La integración de sistemas de fotovoltaicos/térmicos (PV/T) y un eficiente aire acondicionado en los edificios permite el suministro de calefacción, refrigeración y electricidad con una reducción de las emisiones de efecto invernadero. Las configuraciones de integración de: a) sistemas fotovoltaicos (PV) con enfriadores eléctricos refrigerados por aire y sistemas de bombas de calor aire-agua; b) sistemas fotovoltaicos/térmicos (PV/T) basados en aire con sistemas de bomba de calor aire-agua; y c) Los sistemas fotovoltaicos/térmicos de baja concentración (LCPV/T) con enfriadores de compresión y absorción tienen un gran potencial para aumentar la proporción de electricidad fotovoltaica in situ. La flexibilidad de incorporar energía LCPV/T para la red bidireccional de baja temperatura en distritos urbanos reduce las pérdidas térmicas y proporciona edificios de productores y consumidores (prosumidores). En comparación con la configuración típica del enfriador de compresión integrado fotovoltaico, la configuración propuesta de LCPV/T junto con los enfriadores de compresión y absorción reduce el período de recuperación en un 10-40% en el edificio de cajas en El Cairo. Sustituir la conexión a la red de agua del campus por el uso de bomba de calor reversible reduce en un 15-30% el coste operativo de refrigeración y calefacción en el edificio de cajas en España.The integration of photovoltaic/thermal (PV/T) and efficient air conditioning systems into buildings allows the provision of heating, cooling and electricity with a reduction in greenhouse emissions. The integration configurations of: a) photovoltaic (PV) systems with air-cooled electric chillers and air-to-water heat pump (HP) systems; b) air-based PV/T systems with air-to-water HP systems; c) Low concentrated photovoltaic/thermal systems (LCPV/T) with compression and absorption chillers; and d) LCPV/T coupled with water-to-water HP have a great potential in boosting the share of onsite PV-electricity. The flexibility of incorporating LCPV/T energy for the bidirectional low temperature network in urban districts reduces thermal losses and provides producer and consumer (prosumer) buildings. In comparison to the typical configuration of PV integrated compression chiller, the proposed configuration of LCPV/T coupled with the compression and absorption chillers reduces the payback period by 10-40% in the case building in Cairo. Substituting the connection to the campus water network with the use of reversibl