scholarly journals Evaluation of long-term operation of combined system for heating the building and preparation of domestic hot water

2018 ◽  
Vol 46 ◽  
pp. 00018
Author(s):  
Dawid Taler ◽  
Rafał Pitry ◽  
Jan Taler
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Summer Season ◽  
Hot Water ◽  
Buffer System ◽  
Generation Efficiency ◽  
Combined System ◽  
Term Operation ◽  
Measuring Period

The paper presents, the results of research on the operation and energy efficiency of a 186 kW gas-fired condensing boiler operating in a hybrid heat source system. The boiler co-operates with an 81.1 kW (electric) brine-to-water compressor heat pump, a 27.4 kW air-to-water heat pump and 6 flat solar collectors. A local, built-in, hybrid heat source is located in a public building and is intended to satisfy the building needs. The study was conducted over a period of 1 year - from 1 September 2014 to 31 August 2015. The gas-fired boiler operates in the heating buffer system all year round. The boiler performance is characterized both in the winter and in the summer season, in terms of the amount of heat produced and the heating power. The calculations results of the heat generation efficiency obtained in the measuring period are also presented

scholarly journals Finite element modeling of geothermal source of heat pump in long-term operation

2020 ◽  
Vol 154 ◽  
pp. 04003
Author(s):  
Elżbieta Hałaj
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Transport Model ◽  
Heat Pumps ◽  
Initial Temperature Distribution ◽  
Term Operation ◽  
Borehole Heat Exchangers

Heat pumps become more and more popular heat source. They can be an alternative choice for obsolete coal fired boilers which are emissive and not ecological. During heat pump installation designing process, especially for heat pumps with higher heating capacity (for example those suppling larger buildings), a simulation of heat balance of ground heat source must be provided. A 3D heat transport model and groundwater flow in the geothermal heat source for heat pump (GSHP) installation was developed in FEFLOW according to Finite Element Modelling Method. The model consists of 25 borehole heat exchangers, arranged with spacing recommended by heat pump branch guidelines. The model consists of both a homogeneous, non-layered domain and a layered domain, which reflected differences in thermal properties of the ground and hydrogeological factors. The initial temperature distribution in the ground was simulating according to conditions typical for Europe in steady state heat flow. Optimal mesh refinement for nodes around borehole heat exchangers were calculated according to Nillert method. The aim of this work is to present influence of geological, hydrogeological factors and borehole arrangement in the energy balance and long term sustainability of the ground source. The thermal changes in the subsurface have been determined for a long term operation (30 years of operation period). Some thermal energy storage applications have also been considered.

Analysis of Regional Suitability of the Ground-Coupled Heat Pump Based on the Shallow Ground Thermal Balance

2009 ◽  
Author(s):  
Yuefen Gao ◽  
Songling Wang ◽  
Guoqiang Zhang
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Heat Pumps ◽  
Scientific Application ◽  
Term Operation ◽  
Ground Heat Exchangers ◽  
Ground Coupled Heat Pumps ◽  
Ground Coupled Heat Pump ◽  
Consistent Performance ◽  
Source And Sink

Ground-coupled heat pump systems use the ground as a heat source and sink either with vertical or horizontal ground heat exchangers (GHXs) to supply heating in winter and cooling in summer. The ground heat source and sink has a near constant temperature, which is well suited to ground-coupled heat pumps, giving them consistent performance, regardless of the outdoor temperature. However, when the heat extracted from and rejected to the ground has great imbalance, the ground temperature will deviate from the original temperature with a long term operation. The deviation can reduce GHX performance greatly. As China has vast territory with variety climate, the annual cooling loads and heating loads are different at different places. And the imbalance between the extracted heat and the rejected heat also varies at different places. Therefore, it is necessary to analysis the regional suitability of the ground-coupled heat pump systems. The imbalance between the extracted heat and the rejected heat is analyzed by taking several typical cities in different climates. The new concepts of the Imbalance Ratio and the Extracted Heat to Rejected Heat Ratio are introduced as the weight factors to measure the imbalance in the ground. The values of the Imbalance Ratio and those of the Extracted Heat to the Rejected Heat Ratio are calculated. The optimum range of the Imbalance Ratio is recommended based on the vast investigation of the ground-coupled heat pumps. Some supplemental systems are put forward to supply heat in winter or to reject heat in summer at the places existing serious heat imbalance. The study is very meaningful to the scientific application of the ground-coupled heat pump systems in China.

Simulation Study on Solar Collector - Air Source Heat Pump Combined System for Space Heating in Cold Region

2012 ◽  
Vol 238 ◽  
pp. 478-481
Author(s):  
Zhen Qing Wang ◽  
Yan Chen ◽  
Hai Xia Wang
Keyword(s):  
Heat Pump ◽  
Simulation Study ◽  
Hot Water ◽  
Office Building ◽  
Space Heating ◽  
Combined System ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Air Source Heat Pump

An air source heat pump system (ASHPS) was set up, which provided space heating and cooling, as well as hot water for an office building in Tianjin. Its operating performance in winter was evaluated based on test data. Considering the local abundant solar radiation and the way to provide energy in an office building, a simulation study was carried out on the combsystem of ASHP and flat plate air collector (FPAC). The effects of collector area and its outlet parameters on the heating performance of ASHP were studied, and the favorable operating and matching mode were recommended. The results indicate that ASHPS is a technically viable method in Tianjin in winter, but not economically, and the air-solar combsystem should be taken into account for its massive replacement for conventional energy.

The Combined Solar with a Dual Heat Source Heat Pump Applied in a Greenhouse Heating System - An Operation Optimization of Water Source Heat Pump

2014 ◽  
Vol 541-542 ◽  
pp. 942-948
Author(s):  
Xian Peng Sun ◽  
Zhi Rong Zou ◽  
Yue Zhang
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Water Source ◽  
Heating System ◽  
Hot Water ◽  
Inlet Temperature ◽  
Pump System ◽  
Operation Optimization ◽  
Temperature Heat ◽  
The Impact

Based on the finite-time thermodynamic theory, an operation optimization, of water source heat pump in the combined solar with a dual heat source heat pump which is applied in a greenhouse heating system, is made. According to the ε-NTU method and entropy theory, heat exchange and balance equations are obtained. The function relationship between COP and the indoor temperature Tn, the ambient temperature Ta, low temperature heat source inlet temperature Tie and high temperature heat source inlet temperature Tic is also obtained. By means of programming, the impact of parameters on the COP and the way of regulating this water source heat pump system are presented in this article. The results show that: when a separate water source heat pump is running, by adjusting the hot water temperature and the match status of each indoor heating system, the energy-saving operation can be realized.

Analysis on the Technical Solutions of the Heat Source of the Geothermal Heat Pump System

2014 ◽  
Vol 953-954 ◽  
pp. 650-654
Author(s):  
Chao Yi Tan ◽  
Hui Zhu ◽  
Hai Hua Hu ◽  
Meng Meng Wang ◽  
Han Qing Wang
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Heat Load ◽  
Hot Water ◽  
Geothermal Heat ◽  
Pump System ◽  
Heat Pump System ◽  
Geothermal Heat Pump ◽  
In Series ◽  
Technical Solutions

Taking the geothermal heat pump system in the campus of Hunan University of Technology for example, three technical solutions of the heat source of the system were analyzed in terms of the condensing heat load, the annual unbalanced heat load and the energy efficiency ratio (EER) of the system. In addition, comparison was conducted among the solutions. The results indicate that the solution 3, which has a cold and hot water integrative unit and hot water unit connected in series, meanwhile has a cooling tower for auxiliary cooling, shows better performance among all the solutions. The analysis on the solution of heat source of geothermal heat pump system, which usually contains the analysis on the condensing heat load, annual unbalanced heat load and EER, is of great significance for the design and development of the geothermal heat pump system with lower coat and higher EER.

The Optimal Peak-Adjusting Parameters of Low-Temperature Heat Source Heating

Solar Energy ◽  
2005 ◽  
Author(s):  
Ronghua Wu ◽  
Chenghu Zhang ◽  
Dexing Sun
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Water System ◽  
Weather Conditions ◽  
Integrated System ◽  
Hot Water ◽  
Cold Weather ◽  
Design Parameters ◽  
Temperature Heat

The integrated low and high temperature heating water system consists of heat pump heat source and boiler heat source. The heat pump heat source abstract heat from low temperature heat source and produce hot water up to 65°C. During mild weather, the 65°C hot water is sufficient for building heating. During cold weather conditions, the boiler heat source will have to be used to produce hot water at 90°C or higher to satisfy the building comfort. To improve the system economy, the integrated system has to maximize the use of the low temperature heat source since it is free. This paper presents a theoretical models and analysis to optimize the system design parameters.

scholarly journals A study on the design and analysis of a gas engine heat pump water heater using shower wastewater as heat source

2019 ◽  
Vol 9 (3) ◽  
pp. 310-318
Author(s):  
Fengguo Liu ◽  
Zhenxi Ma ◽  
Rui Zhang
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Primary Energy ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Flow Mode ◽  
Outlet Temperature ◽  
Water Heater ◽  
Gas Engine ◽  
Heat Pump Water Heater

Abstract Shower wastewater contains large amounts of heat, and recovering and utilizing shower wastewater heat energy to heat shower water is of great significance for energy saving. This paper proposed a gas engine heat pump water heater (GEHPWH) using shower wastewater as the heat source. Thermodynamic models were built to evaluate the performance of the GEHPWH and compare it with an electrical heat pump water heater (EHPWH). The results show that the GEHPWH has higher hot water outlet temperature and coefficient of performance (COP) than the EHPWH under the same conditions. Furthermore, the GEHPWH can maintain stable hot water outlet temperature and higher primary energy ratio (PER) in variable water flow mode, which resolves the issue that the conventional EHPWH needs an auxiliary heat source. Finally, based on a case, the GEHPWH reveals smaller energy consumption and lower operating costs compared with three other conventional hot-water schemes.

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