The Potential and Utilization of Unused Energy Sources for Large-Scale Horticulture Facility Applications under Korean Climatic Conditions

Abstract

Abstract:As the use of fossil fuel has increased, not only in construction, but also in agriculture due to the drastic industrial development in recent times, the problems of heating costs and global warming are getting worse. Therefore, introduction of more reliable and environmentally-friendly alternative energy sources has become urgent and the same trend is found in large-scale horticulture facilities. In this study, among many alternative energy sources, we investigated the reserves and the potential of various different unused energy sources which have infinite potential, but are nowadays wasted due to limitations in their utilization. In addition, we utilized available unused energy as a heat source for a heat pump in a large-scale horticulture facility and analyzed its feasibility through EnergyPlus simulation modeling. Accordingly, the discharge flow rate from the Fan Coil Unit (FCU) in the horticulture facility, the discharge air temperature, and the return temperature were analyzed. The performance and heat consumption of each heat source were compared with those of conventional boilers. The result showed that the power load of the heat pump was decreased and thus the heat efficiency was increased as the temperature of the heat source was increased. Among the analyzed heat sources, power plant waste heat which had the highest heat source temperature consumed the least electric energy and showed the highest efficiency. OPEN ACCESSEnergies 2014, 7 4782

Energetic and Economic Assessment of Pipe Network Effects on Unused Energy Source System Performance in Large-Scale Horticulture Facilities

“…The EnergyPlus simulation model was established through the modeling of a previous study [6], and it is as shown in Figure 1. The model shape was rectangular which was one of most basic installation models of a vinyl greenhouse.…”

“…The base model of this study is the model of the preceeding study [6], and the basic heat source for each case is as shown in Table 4. Case 1 is the base case, and the cold water and hot water supplied to the FCU are produced using an existing gas boiler and a frequently used refrigerator.…”

“…Case 5 is the heat pump which uses power plant waste heat as the heat source. Lastly, Case 6 is the heat pump which uses geothermal heat as the heat source, and the temperature on the winter season for each case has been described in detail in a previous study [6]. …”

“…Also, the load required for this simulation modeling is 1100 kW [6]. Therefore, it is assumed that ten 30RT heat pumps are used.…”

“…Jung [5] compared the greenhouse gas emissions between the geothermal heat pump and air heat and a gas engine heat pump and confirmed that the greenhouse gas emissions from the outdoor air heat pump and gas engine heat pump were 18.1% and 8.1% higher than the greenhouse gas emissions from the geothermal heat pump respectively. Hyun et al [6] identified outdoor air, sea water, river water, power plant waste heat and geothermal heat as various unused energy heat sources and confirmed the energy consumption according to each heat source by applying a heat pump to a horticulture facility. Also, Lee et al [7] carried out an analysis of the energy according to the distance from a heat source by applying a heat pump using various unused energies as the heat source for a horticulture facility, analyzing the actual temperature range of the energy sources brought in to the heat pump and the energy usage as the distance from the heat source increased and drew the conclusion that among various heat sources the heat pump using the thermal effluent of power plants was the most effective.…”