Energy-saving analysis of air source heat pump integrated with a water storage tank for heating applications

2020 ◽  
Vol 180 ◽  
pp. 107029
Author(s):  
Pin Wu ◽  
Zhichao Wang ◽  
Xiaofeng Li ◽  
Zhaowei Xu ◽  
Yingxia Yang ◽  
...  
2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Azzam Abu-Rayash ◽  
Ibrahim Dincer

Abstract This paper features the integration of two renewable energy sources, making a new trigeneration system for residential applications. The system is primarily powered by solar photovoltaic-thermal (PVT) along with geothermal energy. This trigeneration system consists of a ground source heat pump, solar system, high-grade and low-grade heat exchangers, a heat pump system, and a water storage tank (WST). The objective of this system is to provide the main commodities for residential use including domestic hot water (DHW), electricity, and space heating. The system is analyzed energetically and exergetically using thermodynamic-based concepts. The overall energy and exergy efficiencies of the proposed system are found to be 86.9% and 74.7%, respectively. In addition, the energy and exergy efficiencies of the PVT system are obtained to be 57.91% and 34.19%, respectively. The exergy destructions at the high-grade heat exchanger and the water storage tank add up to 36.9 kW, which makes up 80% of the total exergy destruction of the system. Additionally, parametric studies are conducted to evaluate the degree of impact that various important parameters have on the overall system performance.


Author(s):  
P P Votsis ◽  
S A Tassou ◽  
D R Wilson ◽  
C J Marquand

This paper investigates the performance of a 1.1 m3 stratified hot water storage tank coupled to a vapour compression heat pump system. A comprehensive data acquisition system has been used to obtain the experimental data from a series of static and dynamic tests. In the static experiments a well-defined thermocline has been achieved and the effects of insulation and tank wall thickness on the preservation of the thermocline have been determined. The results indicate that thermal losses in stratified tanks are about 22 per cent higher than the losses in fully mixed tanks. The dynamic experiments have been conducted with an upward-moving thermocline and the major factors influencing its stability have been correlated in terms of the Archimedes number (Gr/Re2). It has been found that good stratification performance can be maintained with Archimedes numbers in the range between 35000 and 55000. A simplified one-dimensional model of the storage tank has been developed and validated against experimental results. The model will be linked to dynamic models of the heat pump and the building to simulate the performance of a heat store/heat pump energy management system.


2014 ◽  
Vol 1051 ◽  
pp. 828-831 ◽  
Author(s):  
Yan Qu ◽  
Fang Wang ◽  
Yu Wang ◽  
Peng Wang ◽  
Tang Li ◽  
...  

Using fluent software simulations to analysis the temperature field and the velocity field of the equal and changing diameter condensing coils at different positions of heat pump water storage tank, and made experiment of R1234-ze on the heat pump water heater storage tank with equal and changing diameter condensing coils ,experimental analysis and simulation results show that changing diameter condensing coils make the tank temperature raise stability, which is beneficial to the stability of the system operation.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4714
Author(s):  
Adnan Rasheed ◽  
Wook Ho Na ◽  
Jong Won Lee ◽  
Hyeon Tae Kim ◽  
Hyun Woo Lee

This study proposes a building energy simulation (BES) model of an air-to-water heat pump (AWHP) system integrated with a multi-span greenhouse using the TRNSYS-18 program. The proposed BES model was validated using an experimental AWHP and a multi-span greenhouse installed in Kyungpook National University, Daegu, South Korea (latitude 35.53° N, longitude 128.36° E, elevation 48 m). Three AWHPs and a water storage tank were used to fulfill the heat energy requirement of the three-span greenhouse with 391.6 m2 of floor area. The model was validated by comparing the following experimental and simulated results, namely, the internal greenhouse temperature, the heating load of the greenhouse, heat supply from the water storage tank to the greenhouse, heat pumps’ output water temperature, power used by the heat pumps, coefficient of performance (COP) of the heat pump, and water storage tank temperature. The BES model’s performance was evaluated by calculating the root mean square error (RMSE) and the Nash–Sutcliffe efficiency (NSE) coefficient of validation results. The overall results correlated well with the experimental and simulated results and encouraged adopting the BES model. The average calculated COP of the AWHP was 2.2 when the outside temperature was as low as −13 °C. The proposed model was designed simply, and detailed information of each step is provided to make it easy to use for engineers, researchers, and consultants.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Musa Manga ◽  
Timothy G. Ngobi ◽  
Lawrence Okeny ◽  
Pamela Acheng ◽  
Hidaya Namakula ◽  
...  

Abstract Background Household water storage remains a necessity in many communities worldwide, especially in the developing countries. Water storage often using tanks/vessels is envisaged to be a source of water contamination, along with related user practices. Several studies have investigated this phenomenon, albeit in isolation. This study aimed at developing a systematic review, focusing on the impacts of water storage tank/vessel features and user practices on water quality. Methods Database searches for relevant peer-reviewed papers and grey literature were done. A systematic criterion was set for the selection of publications and after scrutinizing 1106 records, 24 were selected. These were further subjected to a quality appraisal, and data was extracted from them to complete the review. Results and discussion Microbiological and physicochemical parameters were the basis for measuring water quality in storage tanks or vessels. Water storage tank/vessel material and retention time had the highest effect on stored water quality along with age, colour, design, and location. Water storage tank/vessel cleaning and hygiene practices like tank/vessel covering were the user practices most investigated by researchers in the literature reviewed and they were seen to have an impact on stored water quality. Conclusions There is evidence in the literature that storage tanks/vessels, and user practices affect water quality. Little is known about the optimal tank/vessel cleaning frequency to ensure safe drinking water quality. More research is required to conclusively determine the best matrix of tank/vessel features and user practices to ensure good water quality.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1321
Author(s):  
Yu-Jin Hwang ◽  
Jae-Weon Jeong

The objective of this research is to establish an appropriate operating strategy for a radiant floor heating system that additionally has an air source heat pump for providing convective air heating separately, leading to heating energy saving and thermal comfort in residential buildings. To determine the appropriate optimal operating ratio of each system taking charge of combined heating systems, the energy consumption of the entire system was drawn, and the adaptive floor surface temperature was reviewed based on international standards and literature on thermal comfort. For processing heating loads with radiant floor heating and air source heating systems, the heating capacity of radiant floor heating by 1 °C variation in floor temperature was calculated, and the remaining heating load was handled by the heating capacity of the convective air heating heat pump. Consequently, when the floor temperature was 25 °C, all heating loads were removed by radiant floor heating only. When handling all heating loads with the heat pump, 59.2% less energy was used compared with radiant floor heating only. Considering the local discomfort of the soles of the feet, the floor temperature is expected to be suitable at 22–23 °C, and 31.5–37.6% energy saving compared with those of radiant floor heating alone were confirmed.


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