Ground source heat pump (GSHP) systems for horticulture greenhouses adjacent to highway interchanges: A case study in South Korea

Although fuel-burning systems have long been used as climate control tools in greenhouses, their energy efficiency remains low, causing hikes in operation costs and sacrificing the quality and quantity of horticulture products, not to mention emitting greenhouse gases. To address these issues, a new geothermal energy supply model was developed for greenhouses close to highway Interchanges (ICs) or Junctions (JCTs). This paper presents a comprehensive effort made with field tests and simulations to validate the proposed model at various locations in South Korea. First, a Ground Source Heat Pump (GSHP) system – a central component of the model - was installed in a greenhouse and its efficiency was evaluated and compared with other fuel-burning systems. Second, cost-benefit analyses were carried out to assess whether the proposed model was investible under four possible operation scenarios. Third, the model was simulated at twenty-four ICs and JCTs along 9 highway routes to illustrate the beneficial effects of the model’s scaled-up deployment. The proposed model yielded the highest net income when a GSHP system was running at full capacity for heating and cooling. The payback periods of the model deployed at multiple sites (24 ICs and JCTs) were fewer than two years relative to AC/boiler systems. These findings indicate that the proposed model can be worthy of investment if it is appropriately operated and deployed in the field. Existing rules and policies could be used to help promote the implementation of the model.