Numerical Assessment of Earth to Air Heat Exchanger with Variable Humidity Conditions in Greenhouses

Di Qi, Chuangyao Zhao, Shixiong Li, Ran Chen and Angui Li
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Di Qi: School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
Chuangyao Zhao: School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
Shixiong Li: School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
Ran Chen: School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
Angui Li: School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China

Energies, 2021, vol. 14, issue 5, 1-18

Abstract: Earth to air heat exchangers are widely utilized to cool or heat passive buildings for energy savings. They often need to deal with high humidity air conditions, especially in the greenhouse due to plant transpiration, and the condensation phenomenon is frequently observed during the cooling process. To evaluate the effect of humidity and condensation on thermal performance, a three dimensional computational fluid dynamic (3D-CFD) model was developed. The distribution of relative humidity in each pipe was investigated, and the impact of inlet air relative humidity on the integrated performance of the earth to air heat exchanger was discussed. The effects of inlet air temperature and volume flow rate were also analyzed. Moreover, the influence of the heat exchanger configurations on the performance of the air condensation was researched. The results indicated that condensation had few effects on the airflow distribution uniformity of the earth to air heat exchanger, while it acted observably on the thermal performance. In addition, humid air in a small diameter pipe tended to condense more easily. Humidity and condensation should be taken into consideration for the design of earth to air heat exchangers in greenhouses during engineering applications.

Keywords: earth to air heat exchanger (EAHE); relative humidity (RH); thermal performance; condensation; uniformity (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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