Energy cost analysis of growing strawberries in a controlled environment chamber

Abstract

The purpose of this paper is to examine the energy cost of strawberry cultivation in a controlled environment chamber. To determine the energy cost, a 2.25 × 5.05 × 2.2 m3 testing room for growing strawberries was set up for the experiment in Chiang Mai, Thailand. Light-emitting diode (LED) grow lighting and air conditioning were used to regulate the environment inside the room to satisfy the strawberry growing requirements. There were 180 strawberry plants in the room. The energy consumption of the room was recorded for about 20 weeks. A computer model of the controlled environment chamber was developed and validated using the TRaNsient SYStem simulation tool (TRNSYS). The validated model was then used to predict the energy cost for one strawberry crop. In addition, the TRNSYS model was used to predict the energy consumption and costs of the room using weather data from five Southeast Asian cities (Chiang Mai, Kuala Lumpur, Yangon, Ho Chi Minh City, and Vientiane). It was found that the energy cost of growing strawberries in the controlled environment chamber in Chiang Mai was 2170 USD/crop cycle (71,500 THB/crop cycle) which is equivalent to 12 USD/plant. It was assumed that the average yield of strawberries would be around 150–400 grams per plant under protected cultivation for about 35 days from the fertilisation of the first flower. Consequently, the predicted energy cost for growing strawberries in the controlled environment chamber in Vientiane was the lowest, at 906 USD per crop cycle (5 USD/plant or 14 USD/kg), because of the low ambient temperature and low electricity tariff.