Simultaneous heating and cooling in museums: evaluation of micro-encapsulated phase change slurry as a thermal storage medium for multi-purpose heat pumps
Room 5
August 25, 3:45 pm-4:00 pm
In museums, air handling units are a classic HVAC solution to achieve the desired indoor environmental conditions. Maintaining specific values of temperature and relative humidity is crucial in these buildings, as these parameters affect the integrity of the artworks. To keep the necessary microclimatic conditions, both heating and cooling may be required simultaneously, depending on the energy balance of the building envelope and the external weather conditions. Typically, separate dedicated heating and cooling generators are used to meet the energy demand at the heat exchangers of the air handling units.
Multi-purpose heat pumps offer an energy-efficient alternative to this traditional paradigm, as they can provide heating and cooling simultaneously by recovering energy at both the condenser and evaporator. However, these units can suffer from the control problems typical of cogeneration, resulting in overproduction of either heating or cooling if the loads are not precisely balanced. To overcome this problem, the integration of thermal storage tanks is essential to store the excess of ‘hot’ and ‘cold’ energy, which can be used at a later time, rather than being lost to the external environment.
However, the size required to store the excess energy can be relevant and reduces the attractiveness of the multi-purpose solution: therefore, in this paper we propose to use a microencapsulated phase change slurry as the storage medium, thus significantly reducing the size of the storage thanks to the latent heat of the organic phase change material. The performance of the multi-purpose heat pump in this configuration is compared with its performance in a more traditional setup using a water thermal storage tank. The results are presented using a simulated case study of a museum in Italy.
The heating and cooling requirements at the air handling unit are evaluated using TRNSYS. In-house developed models of the heat pump and thermal storage, based on real data gathered from monitoring campaigns and specific experimental tests, are integrated into the TRNSYS model to evaluate the overall performance of the system.
Presenters
Dr Eva Schito
University of Pisa