Experimental evaluation of localized air temperature profile and performance of serpentine copper tube heat exchanger for energy-saving crop cultivation

Abstract

The objective of this study is to examine the localized air temperature profile and heat transfer performance of a serpentine copper tube heat exchanger. Particularly, the air temperature nearby the plants is controlled by the heat exchanger. The novelty of this study is to provide localized climate control only near the plants targeting periodic air temperature control with the proposed heat exchanger. This study focuses on heating and cooling for cultivation in temperate and tropical regions. In contrast to fin-and-tube heat exchangers, the serpentine heat exchanger has a simple design, provides minimal shade for plants, and is easy to maintain. This study was conducted in a laboratory. The experimental system was constructed under with the assumption that a part of actual plant cultivation was being left out. The experiments were implemented by varying the experimental operating conditions such as the inlet fluid temperature and fluid flow rate in the heat exchanger. The pressure drop in the heat exchanger was also measured. The results revealed that this heat exchanger could provide localized air temperature control. The maximum air temperature difference can be obtained at approximately 12 °C during cooling and heating from their initial air temperature even though the heat exchange is simple. The effects of decreasing the inlet fluid temperature for cooling and increasing the inlet fluid temperature for heating were more dominant than the effect of the flow rate. This simple, low-maintenance, and low-cost serpentine copper tube heat exchanger can effectively provide alternate heating and cooling for plant cultivation.

Keywords

• Localized air temperature
• Heat flux
• Pressure drop
• Cooling/heating
• Serpentine
• Heat exchanger