Part-Load Ratio Research on Energy Consumption of Heat Pump System

Author(s):  
Ru Chang ◽  
Qi dong Yu ◽  
Neng Zhu
2015 ◽  
Vol 1092-1093 ◽  
pp. 26-35
Author(s):  
Jun Jie Zhang ◽  
Ling Hong Xu ◽  
Heng Min ◽  
Ling Yun Wang

The imbalance in cold and heat load in large public buildings located in a cooling-dominated areas is apparent. To explore the effect of a cumulative cold and heat load ratio (CCHLR) on the performance parameters of the hybrid ground-source heat pump system (HGSHPS) of large public buildings, this study selects a Wuhan office building as the simulation object. When this model is considered as the prototype, five other building models whose CCHLR interval is relatively uniform can be developed. The full-year dynamic loads of the six models were calculated with Designer’s Simulation Toolkits. The 20-year simulation of the six HGSHPS models was conducted with TRNSYS. Then, the performance parameters of the HGSHPS model under different CCHLR values were studied and compared. These parameters included the average soil temperature, exiting fluid temperature (ExFT) of the ground heat exchanger (GHE), average energy efficiency ratio, and specific energy consumption (the electrical energy required to obtain per kilowatt cooling or heating capacity) of the heat pump system. Simulation results indicated that with the increase in CCHLR, the average soil temperature rapidly increases, the ExFT of the GHE increases to a value that is considerably higher than the suggested standard, and the specific energy consumption of the system increases.


HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4306 ◽  
Author(s):  
Zhongting Hu ◽  
Sheng Zhang ◽  
Wenfeng Chu ◽  
Wei He ◽  
Cairui Yu ◽  
...  

The present work investigated a solar assisted heat pump system for drying Chinese wolfberry. The kinetic characteristic was firstly analyzed through a series of lab experiments. It was concluded that the Page model was the most suitable for predicting the heat and mass transfer of the wolfberry. Based on the wolfberry kinetic model, solar collector model and chamber air model, the coupled drying system model was developed. The accuracy of the mathematic model was determined through comparing with the preliminary experimental results. The influence of operating conditions on the thermal and energy performance of the dryer for the different operating mode was discussed. The drying weight of no more than 75 kg may be preferable in the stand-alone solar drying mode, and less than 15 h was needed to be dried. The electric energy consumption in the solar assisted the heat pump drying mode was lower than that in the stand-alone heat pump mode, and it was recommended that about 50 kg of wolfberry to be dried in the solar assisted heat pump system. Compared to the autumn drying, the reduction in the electric energy consumption was around 9.1 kWh during the 11 h summer drying process. The obtained results demonstrated the feasibility of the combined system for drying wolfberry, and also can provide the basic theoretical and experimental data support for the following research.


2021 ◽  
Author(s):  
Kajen Ethirveerasingham

The feasibility of a Natural Gas Absorption Heat Pump (GAHP) was investigated through the use of a technology screening tool developed in Excel and TRNSYS simulations that used experimentally evaluated performance curves using 50% propylene glycol (PG)/water solution. The Excel tool was used for cost and greenhouse gas (GHG) reductions analysis and indicated that the GAHP was cost effective compared to an Air-Source Heat Pump (ASHP) in locations where the primary heating fuel was natural gas and had significantly lower GHG emissions compared to a 90% efficient natural gas furnace. During the heating season, it was found that the system only had more than 100% heating Gas Utilization Efficiency (GUE) at -1.5°C or above and would go as low at 66% GUE at nominal flow and return temperatures. Part load performance was analyzed using experimental data and implemented in a TRNSYS model. The TRNSYS model shows significant losses from part load performance and 50% PG/water derating for both heating and cooling season due to excessive cycling.


Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 356
Author(s):  
Fujen Wang ◽  
Kusnandar ◽  
Hungwen Lin ◽  
Minghua Tsai

With the cost of energy rising, the value of conservation grows. Interest in energy efficiency could be a sound investment or a necessary public policy. Heat pump systems provide economical alternatives of recovering heat from different sources for use in various applications. The objective of this study is to present the strategic approach on the energy efficient analysis of the water heating system retrofitted by applying a heat pump system in the dormitory of a university. Energy savings were determined by comparing field measurements of water consumption, water temperature and power consumption of the overall system before (electric resistance heating system) and after (heat pump heating system) the implementation of this project. Furthermore, the building energy simulation code (eQuest) has been applied to verify and predict the long-term energy consumption for both water heating systems. The results from energy modelling revealed the good agreement for energy simulation and field measurement data and the improvement of energy efficiency and energy savings could be achieved satisfactorily by retrofitting of a heat pump system. The energy conversion efficiency of hot water for energy consumption at 0.63 (Mcal/Mcal) could be achieved after the application of heat pump water heating system. It also presented the annual saving about USD 20,000 (NTD 600,000) for the dorm by using a heat pump heating system under the electrical billing rate of Taiwan.


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