scholarly journals A Numerical Study on System Performance of Groundwater Heat Pumps

Energies ◽  
2015 ◽  
Vol 9 (1) ◽  
pp. 4 ◽  
Author(s):  
Jinsang Kim ◽  
Yujin Nam
Keyword(s):  
System Performance ◽  
Numerical Study ◽  
Heat Pumps ◽  
Groundwater Heat Pumps

scholarly journals A Numerical Study on the Performance of Ground Heat Exchanger Buried in Fractured Rock Bodies

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1647
Author(s):  
Weisong Zhou ◽  
Peng Pei ◽  
Dingyi Hao ◽  
Chen Wang
Keyword(s):  
Numerical Study ◽  
Fractured Rock ◽  
Unit Length ◽  
Heat Pumps ◽  
Injection Rate ◽  
Coefficient Of Performance ◽  
Outlet Temperature ◽  
Three Dimensional Model ◽  
Rock Body ◽  
Heat Injection

The ground source heat pump (GSHP) is receiving increasing attention due to the global trend of energy-saving and emission reduction. However, projects with ground heat exchangers (GHEs) buried in fractured rock bodies are scarce, and the impacts of water flow in fractures on the system performance are short of detailed investigations. In this paper, a three-dimensional model was built to study the temperature distribution underground and the relative performance of heat pumps and GHEs influenced by groundwater flow in fractures. Three factors including fluid flow velocities in fractures, the number of fractures and the distributions of fractures were taken into consideration, a range of indicators including outlet temperature of GHEs, mean temperature of “Energy Storage Rock Body” (ESRB) and heat injection rate per unit length were examined. It was found that the heat injection rate per unit length of a U-pipe in fractured rock body could be up to 78.83% higher than that of a U-pipe in integrated rock. Likewise, the coefficient of performance of cases with fractures was identified to be up to 4.50% higher than the integrated rock case. In addition, differently distributed fractures also have different impacts on the heat transfer efficiency of heat pumps and GHEs.

Design, Simulation and Preliminary Results of an All Electric Net-Zero Energy Solar Home

2008 ◽  
Author(s):  
Benjamin P. Barnes ◽  
Luis A. Martinez ◽  
Trishan Esram ◽  
Ty A. Newell ◽  
Patrick L. Chapman
Keyword(s):  
Mechanical System ◽  
System Performance ◽  
Heat Pumps ◽  
Electrical System ◽  
Zero Energy ◽  
University Of Illinois ◽  
Solar Decathlon ◽  
Net Zero Energy ◽  
Net Zero ◽  
The University

This paper describes the mechanical systems, the DC-coupled electrical system, the simulation approach and the preliminary results of the University of Illinois entry in the 2007 Department of Energy Solar Decathlon competition. The competition showcased twenty net-zero energy solar powered houses. The University of Illinois entry was the only one that featured an all-electric design. No solar thermal collectors were used; space and water heating was accomplished primarily through heat pumps. Each of three house modules is sensibly conditioned with autonomous, custom mini-split heat pumps using all radiant and natural convection heat exchange for the interior side. Simulation methods are described and assumptions of wall and window properties, mechanical system performance and electrical system performance are disclosed. Details are provided on the theoretical analysis of internal heat transfer and the basic design of the custom mechanical system. The electrical system topology and equipment choices are presented and initial performance results are shown. Additionally, preliminary analysis is carried out on the data taken during the Solar Decathlon competition and on the observations of post-competition winter performance. The success in being awarded comfort conditioning points during the competition is discussed along with drawbacks not represented in the competition results.

Effect of Operating Conditions on the Performance of Two-Bed Closed-Cycle Solid-Sorption Heat Pump Systems

1995 ◽  
Vol 117 (3) ◽  
pp. 181-186 ◽  
Author(s):  
W. Zheng ◽  
W. M. Worek ◽  
G. Nowakowski
Keyword(s):  
Ambient Temperature ◽  
System Performance ◽  
Cooling Capacity ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Operating Parameters ◽  
Closed Cycle ◽  
Sorption Heat ◽  
Cycling Speed ◽  
Sorption Heat Pump

The effect of two operating parameters, the regeneration temperature and the ambient temperature, on the performance of two-bed, closed-cycle solid-sorption heat pumps is investigated. The results show that increasing the regeneration temperature can improve both the COP and cooling capacity, and the effect on cooling capacity is more significant than the COP. Increasing the regeneration temperature from 180°C to 260°C, the cooling capacity increases by 50 percent and the COP improves 20 percent. When the ambient temperature drops, the system performance increases significantly. When the ambient temperature decreases by 10°C from the design point of 35°C, the COP and cooling capacity increases by 50 percent and 40 percent, respectively. Also, the bed cycling speed should be increased to achieve the optimum system performance when the regeneration temperature is higher or the ambient temperature becomes lower.

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