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

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%.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Akbar Alidadi Shamsabadi ◽  
Mehdi Jahangiri ◽  
Tayebeh Rezaei ◽  
Rouhollah Yadollahi Farsani ◽  
Ali Seryani ◽  
...  

Purpose In this study, a solar water heating system along with a seasonal thermal energy storage and a heat pump is designed for a villa with an area of 192 m2 in Tehran, the capital of Iran. Design/methodology/approach According to the material and the area of the residential space, the required heating of the building was calculated manually and then the thermodynamic analysis of the system and simulation was done in MATLAB software. Finally, regarding the waste of system, an efficient solar heating system, providing all the required energy to heat the building, was obtained. Findings The surface area of the solar collector is equal to 46 m2, the capacity of the tank is about 2,850 m3, insulation thickness stands at 55 cm and the coefficient of performance in required heat pump is accounted to about 9.02. Also, according to the assessments, the maximum level of received energy by the collector in this system occurs at a maximum temperature of 68ºC. Originality/value To the best of the authors’ knowledge, in the present work, for the first time, using mathematical modeling and analyzing of the first and second laws of thermodynamics, as well as using of computational code in MATLAB software environment, the solar-assisted ground source heat pump system is simulated in a residential unit located in Tehran.


2005 ◽  
Vol 128 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Onder Ozgener ◽  
Arif Hepbasli

The main objective in doing the present study is twofold, namely (i) to review briefly the utilization of geothermally heated greenhouses and geothermal heat pumps in Turkey, since the system studied utilizes both renewable energy resources and (ii) to present the Analytical Hierarchy Process (AHP) as a potential decision making method for use in a greenhouse integrated solar assisted geothermal heat pump system (GISAGHPS), which was installed in the Solar Energy Institute of Ege University, Izmir, Turkey. This investigation may also be regarded as the one of the limited studies on the application of the AHP method to GISAGHPs, as no studies on the GISAGHPS have appeared in the literature. In this context, an economic analysis is performed based on the life cycle costing technique first. The results are then evaluated by applying the AHP method to a study, which is a comparative study on the GISAGHPS and split system. The results indicated that the GISAGHPS is economically preferable to the conventional split heating/cooling system under Turkey’s conditions.


Author(s):  
AA Ammar ◽  
K Sopian ◽  
M Mohanraj

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.


1998 ◽  
Vol 120 (4) ◽  
pp. 282-288 ◽  
Author(s):  
K. Den Braven ◽  
E. Nielson

A large portion of the installation cost of a ground-coupled heat pump system is for the excavation necessary for ground coil placement. One possible method of reducing this cost is to place the ground coils beneath the slab floor of the building. This configuration of ground coil placement has not been specifically addressed in previous research. Freezing of the soil must be avoided in such a system. To simulate the temperature response of the surrounding soil to heat pump operation, a computer model was developed which incorporates line source theory in the form of a system of rings. The fluid temperature change along the length of the coil was used to determine the distribution of the ground load throughout the ring system. The model includes an adiabatic upper boundary, seasonal soil temperature variation, and thermal interference throughout the system. Using these results, the minimum soil temperature over a season was predicted. Based on these results, design recommendations for ground coil installation are provided based on available area, soil type, heat extraction rate, depth of coil beneath the slab floor, and depth of slab floor below grade. These include recommendations for pipe spacing, flow direction, and a method to determine whether this type of system is feasible for installation in a particular location.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3269 ◽  
Author(s):  
Zhongbao Liu ◽  
Fengfei Lou ◽  
Xin Qi ◽  
Yiyao Shen

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.


Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 31
Author(s):  
Jihyun Hwang ◽  
Doosam Song ◽  
Taewon Lee

Geothermal source heat pump (GSHP) systems as renewable energy systems are being more frequently installed as part of the zero-energy building drive. However, in South Korea, where a large amount of heating load can be required, maintaining high system performance by using only a GSHP is difficult owing to the gradual degradation of its thermal performance. The performance of a solar-assisted GSHP system was therefore experimentally analyzed and compared with a GSHP-only system. The results showed that the heating coefficient of performance of the GSHP-only operation was 5.4, while that of the solar-assisted GSHP operation was 7.0. In the case of the GSHP-only system, the maximum temperature of the heat pump water supply on the heat source side was initially 13.1 °C, but this rapidly decreased to 11.4 °C during operation. For the solar-assisted GSHP system, the temperature of the water supply to the heat source side of the heat pump was controlled at 15–20.9 °C, and the power consumption for system operation was reduced by about 20% compared with that for the GSHP-only system. Much higher temperatures could be supplied when solar heat is used instead of ground heat, as solar heat contributes to the performance improvement of the heat pump system.


2014 ◽  
Vol 18 (5) ◽  
pp. 1673-1677
Author(s):  
Xian-Ping Zhang ◽  
Xin-Li Wei ◽  
Xiao-Wei Fan ◽  
Fu-Jun Ju ◽  
Lei Yang

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.


2021 ◽  
Vol 246 ◽  
pp. 06001
Author(s):  
Petri Pylsy ◽  
Jarek Kurnitski

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.


2013 ◽  
Vol 21 (03) ◽  
pp. 1330002 ◽  
Author(s):  
KOJO ATTA AIKINS ◽  
SANG-HYEOK LEE ◽  
JONG MIN CHOI

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%.


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