Evaluation and Short-Term Test on Potential Utilization of Ground Source Heat Pump for Space Cooling in Southeast Asia

The cooling of spaces in tropical regions, such as Southeast Asia, consumes a lot of energy. Additionally, rapid population and economic growth are resulting in an increasing demand for space cooling. The ground-source heat pump has been proven a reliable, cost-effective, safe, and environmentally-friendly alternative for cooling and heating spaces in various countries. In tropical countries, the presumption that the ground-source heat pump may not provide better thermal performance than the normal air-source heat pump arises because the difference between ground and atmospheric temperatures is essentially low. This paper reports the potential use of a ground-source heat pump with horizontal heat exchangers in a tropical country—Thailand. Daily operational data of two ground-source heat pumps and an air-source heat pump during a two-month operation are analyzed and compared. Life cycle cost analysis and CO2 emission estimation are adopted to evaluate the economic value of ground-source heat pump investment and potential CO2 reduction through the use of ground-source heat pumps, in comparison with the case for air-source heat pumps. It was found that the ground-source heat pumps consume 17.1% and 18.4% less electricity than the air-source heat pump during this period. Local production of heat pumps and heat exchangers, as well as rapid regional economic growth, can be positive factors for future ground-source heat pump application, not only in Thailand but also southeast Asian countries.

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A Simulink®-Based Building Load-Ground Source Heat Pump Model Used to Assess Short-and Long-Term Heat Pump and Ground Loop Performance

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4026081 ◽

2014 ◽

Vol 6 (2) ◽

Cited By ~ 2

Author(s):

Jonathan L. Gaspredes ◽

Glenn. Y. Masada ◽

Tess. J. Moon

Keyword(s):

Heat Pump ◽

Loop Model ◽

Ground Model ◽

Ground Source Heat Pump ◽

Short Term ◽

Ground Source ◽

Wide Range ◽

Building Load ◽

Ground Loop

An integrated building load-ground source heat pump model is developed to capture short-term (30 s) and long-term (10–20 yr) performance of ground source heat pumps with vertical boreholes. The model takes advantage of the built-in computation and organization functions of the simulink®/matlab environment to couple the component building load, heat pump, and ground loop models at every time step. The building load model uses the HAMBASE thermal program and is applicable to residential and commercial buildings. The heat pump model uses manufacturer data and sensible heat corrections to accurately model heat pump operation across a wide range of input conditions. The ground loop model is a combination of Hellstrom's borehole tube model, Eskillson's long-term (>10 yr) g-function ground model and the one-dimensional, short-term (<5 min) numerical ground model by Xu. Fifteen year simulation results for a base case residential house are presented to illustrate the integrated model's ability to predict a wide range of time responses and to illustrate a limiting ground loop sizing criterion that reveals the slow degradation in system performance due ground heating effects. Simulations with varying borehole lengths also illustrate the sensitivity of ground loop sizing on the system's thermal and economic performances. The work emphasizes the importance of proper borehole sizing, design, and placement especially in cooling-dominated climates, where the unbalance of heat loads to the ground cause slowly rising ground temperatures.

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