Assessment of heating and cooling demands of a glass greenhouse in Bucharest, Romania

In southern parts of Europe, a balanced use of both heating and cooling is required to control the greenhouse temperatures throughout the year. Especially, with climate change and increasingly hot summers, the need for efficient greenhouse cooling and humidity control has become more and more important. In this work, we investigate the heating and cooling demands of a glass greenhouse located in Bucharest, Romania (latitude 44 degrees 28 ' 12 '' N, longitude 26 degrees 3 ' 41 '' E). The IDA Indoor Climate and Energy (IDA ICE) software is applied for the assessment of the energy demands, with weather data supplied using the integrated International Weather for Energy Calculations (IWEC) file for Bucharest. With a 2-degree wide deadband, the temperatures of the greenhouse compartments are set to 25 degrees C and 19 degrees C for day and night, respectively. The simulation gives an annual heating demand of 1,715 MWh for the greenhouse, corresponding to 638 kWh/m2. The annual cooling demand is 1739 MWh, corresponding to 647 kWh/m2. The maximum daily cooling load averages about 730 kW during the hottest summer months, while the maximum heat load averages about 590 kW for the coldest winter months. A novel, energy-efficient concept to be installed at the greenhouse, comprising an integrated heat pump system, air handling units, dry coolers, and the utilization of borehole thermal energy storage (BTES), is discussed in terms of the main principles and the required capacities of the system.