Renewable energy sources used for a low energy University building

Abstract

Nowadays, the renewable energy sources have to be implemented in every new building. This paper describes the case study, and related simulations, of a university building in Romania, that has to become zero energy. Ground source heat pumps (GSHP) are ideal to be implemented in new buildings, being able to produce either heating and cooling. A good insulation is important too, to reduce the cooling and heating energetic needs. Asides active cooling, the passive cooling should be taken into account because it can lower the cooling consumption. For the domestic hot water (DHW), solar panels are taken into consideration to reduce at least 60-70% of the energy consumption, for DHW only. To be able to accomplish the goal of a near zero energy building, photovoltaic solar panels are taken into consideration, placed on the terrace of the building, the system being off-grid type. For all the dynamic simulations Designbuilder software was used, a powerful simulation tool which is able to model all renewable energy sources above mentioned. Also very detailed yearly energetic consumption is presented for all types of consumers from the building: heating, cooling, lighting, ventilation, heating, cooling and domestic hot water. Concerning ventilation, a recovery heat exchanger is used in simulations, having a 80% efficiency, also to reduce the energy consumption. The energy between building and heat pump is using fan coils in all the occupied areas,. Finally, regarding the results of the simulations, after a good insulation of the building and the implementation of the geothermal heat pump, heat recovery unit, solar thermal and solar photovoltaic solar panels, a zero energy building has been obtained. The simulated building had initially a poor energy efficiency, without proper insulation but also with old heating and cooling systems. For the characteristics of the soil measurements with thermal response test (TRT) method from Bucharest were used. Dynamical simulation is one of the best methods to simulate as accurate as possible energy consumption for several case studies, varying insulation type and thickness and different heating/cooling systems.