Case Studies

Heat Exchangers

Heat exchangers create a transfer of thermal energy from one thing to another.

Often, we take hot or cold water and flow it through an array of pipes. Air passes over the pipes and thermal energy is transferred from hot water to warm the air or from warmer air to cooler water, cooling the air.

Hot and Cold Water Loops

Our campus heats water by combustion in a central location and distributes it across campus. The water flows through heat exchangers and warms the air in the buildings.

We do the same with cold water using electric chillers.

Campus Heating Loop

Our heating loop runs at about 700 gpm with a 20F temperature drop. Currently the supply temperature ranges from 160F to 240F and we have a target of dropping the supply temp to 140F.

On Demand Water Heating

Traditional water heating uses a tank for storage of hot water. In an on-demand system, water flows through tubes that are heated by combustion or electricity.

The power delivered to the water is equal to the specific heat capacity times the temperature difference times the rate of flow.

District Heating

There are efforts to use the natural gas infrastructure as a system for distributing heating and cooling. Homes can extract or deposit thermal energy into water circulating in the pipes creating a shared thermal resource for a neighborhood.

HEET

Hot Rock Storage

There are several companies using the heat capacity of graphite bricks to store energy.

They can retrieve this energy as heat or as electricity using thermo-photo-voltaics.

Geothermal Heat Exchange