Heating Performance Analysis of an Air-to-Water Heat Pump Using Underground Air for Greenhouse Farming

Abstract

As one of the main businesses in Jeju-do in South Korea, specialized local products are grown in greenhouses. For greenhouse farming, it is preferable to use geothermal heat pump systems for energy conservation because of the stable temperature of the ground. In the same manner, heat pumps using underground air is recommended for greenhouse farming since underground air can easily be obtained from porous volcanic rocks in Jeju-do. However, direct usage of the underground air is not feasible for planting in the greenhouse or livestock care because the underground air is relatively humid and its temperature is low. For the present study, the heating performance of an air-to-water heat pump which used underground air as a heat source for greenhouse farming during the winter was assessed through measurements. In addition, the economic impact of the air-to-water heat pump (AWHP) was compared with a conventional air heater. According to the results, an AWHP can save more than 70% of the total heating costs compared with a conventional air heater. In sum, the utilization of the air-to-water heat pump using underground air can have a positive impact on reducing energy consumption as well as provide direct economic benefits.

Demand-Side Flexibility in Power Systems: A Survey of Residential, Industrial, Commercial, and Agricultural Sectors

“…In greenhouse farms, the operation of cooling and heating systems can provide power flexibility [147]. The heat pumps are addressed not only to increase the energy efficiency of greenhouse farming but also to decrease CO 2 emissions.…”

Buildings Energy Efficiency and Innovative Energy Systems

“…In "Heating Performance Analysis of an Air-to-Water Heat Pump Using Underground Air for Greenhouse Farming", Lim et al assess, with measurements, the heating performance of an air-to-water heat pump that used underground air as a heat source for greenhouse farming during the winter. They show that AWHP (air-to-water heat pump) can save more than 70% of the total heating costs compared with a conventional air heater [10].…”

Runaround coils as a way to improve the efficiency of heat pumps for the dehumidification of nordic greenhouses

“…They suggested using this technique in a greenhouse with lower heating setpoints to maximize the economy generated by this system. Other authors used underground air from a volcanic site as a source for an air to water heat pump used for greenhouse heating [16].…”