Study on Calculation Models of Earth-Air Heat Exchanger Systems

Abstract

Modeling is very useful tool in order to predict the effect of the operating parameters like pipe length, radius, depth of burial and air flow rate on the thermal performance and heating/cooling capacity of earth-air heat exchanger (EAHE) systems. Till date many researchers have carried out a number of studies on calculation models for earth-air heat exchanger systems. The analysis of EAHE systems started with the development of one-dimensional models. The two-dimensional models came into practice during the 1990s and were replaced by three-dimensional models in recent years. Latest models are dynamic and technically more advanced which can provide room for all types of grid geometry to produce detailed thermal analysis of EAHE systems. This paper reviews on calculation models of EAHE systems as of the end of March, 2014.

Parametric Optimization of Earth to Air Heat Exchanger Using Response Surface Method

“…EAHE systems are divided into subgroups based on their configuration and design into open-loop and closed-loop EAHEs. Open loop EAHEs draw air directly from the atmosphere as shown in Figure 1a, while closed-loop EAHEs loop the air from a building until the desired temperature is achieved as shown in Figure 1b [12]. EAHEs can become a viable alternative to conventional air conditioning systems while giving a simplistic design and mitigating environmental concerns and costs at the same time [13].…”

“…EAHEs can become a viable alternative to conventional air conditioning systems while giving a simplistic design and mitigating environmental concerns and costs at the same time [13]. The open loop system is preferred over closed loop as it provides the clean fresh air that circulates through pipes and meets the building cooling/heating requirements as compared to the closed loop where the same air is recirculated through the pipes [12].…”

Potential cooling savings from a ground-coupled return-air duct system for residential buildings in hot and humid climates

“…The EAHE system is typically installed using 30 to 60 meters of buried horizontal pipes, 2 to 4 meters under ground level [5,6]. The pipes are slightly inclined to remove any condensed water inside [7][8][9].…”

“…The EAHE system can be categorized as either open-loop or closed-loop [9]. The open-loop EAHE system is designed to achieve both indoor air comfort and less energy consumption in buildings by taking fresh outdoor air through buried pipes into indoor spaces.…”

“…The open-loop EAHE system is designed to achieve both indoor air comfort and less energy consumption in buildings by taking fresh outdoor air through buried pipes into indoor spaces. Due to indoor air quality regulations (e.g., air change hour rates), the open-loop EAHE system is more suitable for commercial, institutional, agricultural, and clinical buildings [9]. On the other hand, the closed-loop EAHE system, which is the ground-coupled return-air duct system used in this study, is designed to improve a building's system efficiency by circulating return-air from indoor spaces through buried EAHE pipes.…”