Strategies for energy efficient renovations and operations at Sundsvall hospital

Sundsvall hospital has many facilities that are heated by electrical air heating and the exhaust air is ventilated through so called exhaust windows. This leads to high air flows and temperature gradients in the rooms. In connection with renovations of building component M09 at the hospital the heat system is replaced with waterborne radiator heating, new supply air devices are installed and the external walls are reinsulated. This thesis aims to investigate how the exhaust windows is affected by lowered air flows and an alternative heating system and how optimal operations is achieved and also what should be prioritized in future renovations. In this thesis two identical rooms, one with the old electrical air heating and the other with waterborne radiators, was investigated. Air temperature, surface temperature and heating power was measured in both rooms with different air flows and heating losses was calculated. IDA ICE is a software for simulations of energy and indoor climate where the measured values was compared with the simulated in IDA ICE to verify a simulation model. IDA ICE was then used to calculate yearly energy use and thermal comfort for different operations and reinsulation thicknesses for both heating systems. The results show that the energy use is mainly affected by the air flow in the room and not as much the heating system or thickness of reinsulation. The thermal comfort is improved with radiator-heating and thicker reinsulation increases the number of hours the room is too hot but the overall thermal comfort is better. The life cycle cost can be lowered with a thinner reinsulation in the room with radiator heating but not in the room with electrical air heating