scholarly journals Energy Efficiency of a Heat Pump System: Case Study in Two Pig Houses

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 662 ◽  
Author(s):  
Hannah Licharz ◽  
Peter Rösmann ◽  
Manuel S. Krommweh ◽  
Ehab Mostafa ◽  
Wolfgang Büscher
Keyword(s):  
Fossil Fuels ◽  
Electrical Current ◽  
Heat Pumps ◽  
West Germany ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
The Third ◽  
Empirical Performance

This study describes a 70-day investigation of three identical groundwater heat pumps (GWHP) for heating two pig houses located on the same farm in West Germany. Two of the three GWHPs were installed in a piglet-rearing barn, the third in a farrowing barn. All three heat pumps were fed from the same extraction well. The aim of this study was firstly the empirical performance measurement of the GWHP systems and secondly the energetic evaluation of the systems on barn level by calculating the coefficient of performance (COP). Three different assessment limits were considered in order to better identify factors influencing the COP. In total, the heat pumps supplied thermal energy of 47,160 kWh (piglet-rearing barn) and 36,500 kWh (farrowing barn). Depending on the assessment limit considered, the COP in piglet-rearing barn and farrowing barn ranged between 2.6–3.4 and 2.5–3.0, respectively. A significant factor influencing the COP is the amount of electrical current required to operate the groundwater feeding pump. The average groundwater flow rate was 168.4 m3 d−1 (piglet-rearing barn) and 99.1 m3 d−1 (farrowing barn). In conclusion, by using energy from groundwater, GWHPs have the potential to substitute fossil fuels, thus saving them and avoiding CO2 emissions.

Photovoltaic thermal collector assisted heat pumps using environment-friendly working fluids

2020 ◽  
pp. 095440892094736
Author(s):  
AA Ammar ◽  
K Sopian ◽  
M Mohanraj
Keyword(s):  
Heat Pump ◽  
Energy Performance ◽  
Heat Pumps ◽  
Payback Period ◽  
Photovoltaic System ◽  
Coefficient Of Performance ◽  
Photovoltaic Module ◽  
Pump System ◽  
Heat Pump System ◽  
Thermal Evaporator

In this research, a photovoltaic-thermal collector assisted heat pump has been developed and tested its performance under the tropical climatic conditions of Malaysia. The refrigerants such as, R134a and R1234yf were selected based on its thermodynamic and thermo-physical properties. The temperature of the photovoltaic module was theoretically predicted under the influence of tube diameter, tube spacing and refrigerant mass flow rate. Further, the energy performance of the photovoltaic-thermal evaporator and the heat pump system are investigated experimentally. Finally, the economical feasibility of the photovoltaic-thermal collector evaporator was assessed for the period of 20 years. The results showed that, the tube spacing and diameter of the copper tubes used in the photovoltaic-thermal evaporator/collector using R134a and R1234yf were optimized to 80 mm and 12.7 mm, respectively. It was observed that, during the clear sunny day, the average photovoltaic module temperature was reduced to 30.9 °C under the influence of panel cooling using refrigerant. The output of the panel was enhanced by 21%–44% with increase in solar radiation from 400 W/m2 to 1000 W/m2. The coefficient of performance of the heat pump was varied from 4.8 to 6.84 with an average coefficient of performance of 5.8 during clear sunny days. The life cycle economic analysis indicated that, the photovoltaic-thermal collector evaporator assisted heat pump has a payback period of 3 years, whereas the reference photovoltaic system has a payback period of 8 years.

Modeling and control of heat pump system for battery electric buses

2022 ◽  
pp. 095440702110694
Author(s):  
Rabih Al Haddad ◽  
Hussein Basma ◽  
Charbel Mansour
Keyword(s):  
Energy Consumption ◽  
Weather Conditions ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Cold Weather ◽  
Pump System ◽  
Heat Pump System ◽  
Battery Capacity ◽  
Driving Range

Given the continuous tightening of emissions regulations on vehicles, battery-electric buses (BEB) play an essential role in the transition toward cleaner transport technologies, as they represent the most promising solution to replace diesel buses and reduce their environmental impact in the short term. However, heating the bus cabin leads to a considerable increase in energy consumption under cold weather conditions, which significantly reduces the driving range, given the limited battery capacity. Heat pumps (HP) are the primary heating technology used in BEB for their improved consumption performance compared to other technologies. Therefore, this study aims at optimizing the coefficient of performance (COP) of an HP system in a BEB for maximizing the bus electric driving range under cold weather conditions while maintaining satisfactory thermal comfort levels for passengers. Accordingly, an HP model is developed and integrated into an electric bus model using Dymola. A genetic algorithm (GA) based controller is proposed to find the optimal combination of the HP operating parameters, namely the compressor speed, the air mass flow rate at the inlet of the condenser, and the recirculation rate in order to maximize the system’s COP, and extend the BEB driving at different external temperatures, and as a function of the passengers’ occupancy levels. Results are carried under transient and steady-state operating conditions and show that the proposed GA-based controller saves up to 39% of the HP energy consumption as compared to the conventional HP control strategy, and therefore, enhances the BEB driving range up to 17%.

scholarly journals Implementation of a geothermal heat pump system in a solar passive house

2019 ◽  
Vol 85 ◽  
pp. 07014
Author(s):  
Gheorghe Ilisei ◽  
Tiberiu Catalina ◽  
Marian Alexandru ◽  
Robert Gavriliuc
Keyword(s):  
Heat Pump ◽  
Electricity Consumption ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Passive House ◽  
Geothermal Heat ◽  
Pump System ◽  
Heat Pump System ◽  
Major Index ◽  
Passive Houses

Underground energy sources are becoming increasingly popular and now geothermal heat pumps are frequently used to heat/cool different types of buildings, including for solar passive houses. This article aims at giving a contribution in the development of the thermal modelling of borehole heat storage systems, investigating the possibility of a GSHP (ground source heat pump) implementation with vertical boreholes in a solar passive house. A case study analysing a residential solar passive house is presented as a suitable modelling tool for the estimation of the thermal behaviour of GSHP systems by combining the outcome from different modelling programs. The software DesignBuilder, Earth Energy Designer and a sizing method for borehole’s length are used for producing the numerical results. The results highlight that the length of the borehole, a major index in estimating the system’s cost, is directly influenced by fundamental variables like thermal conductivity of grout or soil. Additionally, correlations between these parameters and the coefficient of performance of GSHP were made. Furthermore, the length of borehole is very important as it is responsible for almost half of the total installation cost and triggered a difference in electricity consumption of the GSHP up to 14%.

Modeling and Experiments on Fast Response Thermoelectric Co-Generation for Intermittent Renewable Energy Sources

2012 ◽  
Author(s):  
Kazuaki Yazawa ◽  
Vernon K. Wong ◽  
Morten Boje Blarke ◽  
Ali Shakouri
Keyword(s):  
Cold Water ◽  
Renewable Energy Sources ◽  
Fast Response ◽  
Heat Pumps ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Power Sources ◽  
Heat Pump System ◽  
Modeling And Experiments

We present preliminary proof-of-concept experimental results on a thermoelectric heat pump system. In our previous work we proposed a thermal battery which would benefit from state-of-the-art heat pumps in order to provide useful cooling and heating. The preliminary analysis demonstrated the benefit of using excess electricity from intermittent renewable power sources, e.g. solar or wind, and converting it into the hot and cold water storage tanks typically used for residential applications. The time response of mechanical heat pumps is slow and their efficiency suffers from fluctuating electricity supplies. To overcome this issue, we propose thermoelectric (TE) co-generation systems that benefit from their fast response and scalability. Modeling has been performed to optimize the TE module for the effective harvesting of both heat and electricity from intermittent solar energy with response times in minutes. Throughout the modeling and experiments, the combined coefficient-of-performance (COP) is found to be 1.6, while the hot water is 52.5°C and cold water is 16.5°C, both from 22.3°C. The COP is moderate, but due to its quick response, the accumulated energy harvested by this thermoelectric system could be comparable to mechanical compressor systems.

scholarly journals Enhancing Heating Performance of Low-Temperature Air Source Heat Pumps Using Compressor Casing Thermal Storage

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3269 ◽  
Author(s):  
Zhongbao Liu ◽  
Fengfei Lou ◽  
Xin Qi ◽  
Yiyao Shen
Keyword(s):  
Low Temperature ◽  
Heat Pump ◽  
Waste Heat ◽  
Thermal Storage ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Discharge Temperature ◽  
Vapor Injection

Air source heat pumps (ASHPs) are widely recognized as energy-saving and environmentally friendly heating and air-conditioning equipment with broad applications. However, when conventional ASHPs are operated at a low ambient temperature, they suffer from problems such as high discharge temperature and low heating efficiency. To address these problems, this study designed a new type of dual evaporator combined with a compressor casing thermal storage heat pump system (DE-CCTS) on the basis of a low-temperature air source heat pump water heater with enhanced vapor injection (EVI). The proposed DE-CCTS used thermal storage phase change material (PCM), which was filled in the secondary evaporator (the thermal storage heat exchanger), to recover the waste heat of the compressor casing. Unlike that in the original system under different ambient temperatures, the suction temperature increased by 0.1–1 °C, the discharge temperature decreased by 0.1–0.5 °C, and the coefficient of performance (COP) of DE-CCTS increased by 0.85–4.72% under the proposed system. These effects were especially evident at low temperatures.

scholarly journals Performance evaluation of heat pump system using R744/R161 mixture refrigerant

2014 ◽  
Vol 18 (5) ◽  
pp. 1673-1677
Author(s):  
Xian-Ping Zhang ◽  
Xin-Li Wei ◽  
Xiao-Wei Fan ◽  
Fu-Jun Ju ◽  
Lei Yang
Keyword(s):  
Heat Pump ◽  
Mass Fraction ◽  
Variable Mass ◽  
Heat Pumps ◽  
Montreal Protocol ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Conservation Technology ◽  
Phase Out

As an efficient and energy conservation technology, heat pumps working with R22, which are scheduled to be phased out by Montreal Protocol, are widely used in China at present. The global deteriorating ecology environment would accelerate the phase-out time of R22 in developing countries. Therefore, as a matter of urgency, an eco-friendly substitute should be investigated in order to replace R22. Under this context, and with a consideration of the environmental protection, R744/R161 mixture refrigerant is proposed. R744/R161 mixture refrigerant?s condensation pressure is reduced and its flammability and explosivity are suppressed. A thermodynamic model is developed, and under the given working conditions, the performances of subcritical heat pump system using R744/R161 mixture of variable mass fraction are discussed and compared with those of the R22 system. The optimal mass fraction of R744/R161 is given, which corresponds to a maximal heating coefficient of performance. The simulation results show that R744/R161 mixture can work as a competitive alternative to R22 in heat pump system.

scholarly journals Measured performance of exhaust air heat pumps in Finnish apartment buildings

2021 ◽  
Vol 246 ◽  
pp. 06001
Author(s):  
Petri Pylsy ◽  
Jarek Kurnitski
Keyword(s):  
Heat Pump ◽  
Ventilation System ◽  
Measurement Data ◽  
District Heating ◽  
Energy Performance ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Apartment Buildings

The energy efficiency of existing apartment buildings is playing an important role in energy and climate targets. In Finland, mechanical exhaust ventilation system is commonly used in older apartment buildings. Hence, there could be an energy saving potential by an exhaust air heat pump system (EAHP). In this work two cases have been studied. Buildings were built in 1960’s and 1970’s and in renovation equipped with hybrid heating system: district heating and exhaust air heat pump system. Two years measurement data, 2018 and 2019, was collected to evaluate the performance of exhaust air heat pump systems. According to measurement data the monthly coefficient of performance (COP) was calculated as well as seasonal coefficient of performance (SCOP) was defined. The monthly COP values varied from 3,1 to 4,6 and SCOP values were about 3,7. Heating energy cost savings were 23-31 %. Energy performance class before and after EAHP installation was calculated. If at least 50 % of heating energy consumption was covered by EAHP then also energy performance class was improved.

TECHNOLOGY REVIEW OF TWO-STAGE VAPOR COMPRESSION HEAT PUMP SYSTEM

2013 ◽  
Vol 21 (03) ◽  
pp. 1330002 ◽  
Author(s):  
KOJO ATTA AIKINS ◽  
SANG-HYEOK LEE ◽  
JONG MIN CHOI
Keyword(s):  
Heat Pump ◽  
High Efficiency ◽  
Industrial Applications ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Two Stage ◽  
Pump System ◽  
Heat Pump System ◽  
Discharge Temperature ◽  
Increasing Demand

There is increasing demand for domestic and industrial refrigeration, space heating and air conditioning. Heat pump systems offer economical alternatives for recovering heat from different sources for use in these applications. As a renewable energy technology for sustainable environment, the heat pump's high efficiency and low environmental impact have already drawn a fair amount of attention all over the world. Some of these domestic and industrial applications require very low evaporating temperatures and very high condensing temperatures which induce high compressor pressure ratios beyond the practical range for single-stage heat pump cycles. These high pressure ratios also produce low coefficient of performance (COP) values and expose the compressor to high discharge temperature, low volumetric efficiency and damage. However, this challenge can be overcome by adopting two-stage heat pump cycles. In this paper, recent works on two-stage heat pump systems for various applications are reviewed. They include two-stage cycle with intercooling, two-stage cycle with refrigerant injection and two-stage cascade cycle. Research and innovative designs of systems that make use of these two-stage cycles have been able to get heat pumps to handle applications with lower and higher temperatures, while enhancing heating capacity up to 30% and COP up to 31%.

scholarly journals Design and Performance Evaluation of a Heat Pump System Utilizing a Permanent Dewatering System

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2273
Author(s):  
Seung-Hoon Park ◽  
Yong-Sung Jang ◽  
Eui-Jong Kim
Keyword(s):  
Energy Source ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Large Scale ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Air Source Heat Pump ◽  
And Performance

The earth provides a vast resource of groundwater from aquifers a few meters beneath the surface. Thus, buildings that use underground space must be equipped with dewatering wells to drain the permeated groundwater to the sewage pipelines to ensure the structural stability of the building. Although the inflowing groundwater temperatures and flow rates are stable enough for groundwater to be used as an energy source, 79% of the permeated groundwater is discarded through the sewers, generating significant sewerage expenses. This study introduced a novel heat exchanger module to utilize the permeated groundwater as an unused energy source using heat pumps, and the performance of the system was evaluated by TRNSYS simulations. First, the sizing of the unit heat exchanger module was proposed according to the mean inflow rate of the permeated groundwater. Second, the heat pump system was configured using multiple modules in the source-side loop. Finally, the performance of the proposed heat pump system was compared with that of a conventional air source heat pump using realistic load and temperature profiles. This preliminary study demonstrated interesting performance results, with a coefficient of performance for heating that was higher than that of a conventional heat pump system by 0.79. The results show the potential utilization of the systems for a construction project requiring large-scale underground spaces, where abundant groundwater is available.

scholarly journals An Experimental Study on External Ventilation to the Heating Performance of Household Air Source Heat Pump

2021 ◽  
Vol 9 ◽  
Author(s):  
Hang Zou ◽  
Zhanqiang Liu ◽  
Enshen Long
Keyword(s):  
Heat Pump ◽  
Great Influence ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Pump System ◽  
Heat Pump System ◽  
Heating Performance ◽  
Air Source Heat Pump ◽  
Ventilation Condition ◽  
Ventilation Conditions

The external ventilation conditions have a great influence on the heating performance of the air source heat pump (ASHP) systems. The outdoor units of residential household air source heat pumps are often installed in narrow spaces such as balconies. The ventilation conditions of the outdoor unit will influent the heating performance of the air source heat pump. It is necessary to study the effect of the outdoor unit ventilation conditions on the heating performance of residential household heat pumps. This paper experimentally studied the heating performances of an air source heat pump system with the outdoor unit mounted in a balcony in different external ventilation conditions. The results indicate that the ventilation conditions for the outdoor units have a significant effect on the heating performance of the system. When the inlet of the outdoor unit was close to the sliding door and completely blocked, the ventilation environment was the worst and the coefficient of performance (COP) was the lowest. In addition, the unfavorable ventilation environment could result in a reduction of the COP by 26.2%. When the inlet of the outdoor unit was partially blocked, the heating performance could be improved and the COP was also slightly improved. The great heating performance was obtained under the cross-ventilation condition. This paper can guide the design of the installation position of the household air source heat pump outdoor units in actual engineering.

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