Ice storage system (ISS) : phase change modelling (TRNSYS 15). Simulation of a typical HVAC primary plant equipped with an ice sotrage unit.

An ice storage can be an interesting option in a HVAC plant. It reduces the electricity costs
and increases the HVAC plant capabilities. ISS reduces the on-peak power and shifts the
cooling demand from the on-peak hours to the off-peak hours. ISS increases the available
HVAC plant power, and then, the internal comfort.
To store cold energy requires the selection of operating strategies. The objective of these
strategies is to meet the global cooling demand of the building. Each strategy offers different
technical and economical characteristics. The typical questions the manager of an HVAC
plant has to solve are: Which is optimal ice storage tank in my case? Which cooling power?
Which cooling capacity? How to run the HVAC plant to minimize the cost?
To compare objectively the strategies, the manager needs to reproduce the ISS performances
for the same conditions (building, cooling and electrical demands, climate conditions,...). He
needs also informations to chose the appropriate plant configuration or operating strategy to
meet the global cooling demand taking into account the characteristics of the tank, of the
demand curve,... at each moment. A simulation model of an entire HVAC primary plant
should provide this information.