The Heat Transfer for Energy Savings Team created a heat recovery system at Herd & Horns to reduce the restaurant’s energy consumption and operating cost.

The Problem

Hot air was exhausted from a condenser into the open attic space above the main dining area. This caused the temperature in that area to rise leading to the use of more air conditioning. The opposite problem was occurring in the men’s restroom. Heat was being lost through the restroom floors and brick wall leading to the outside. This caused the temperature to drop to an uncomfortable level.

The Solution

Energy from the hot air condenser was transferred to water from a cross flow heat exchanger. A fan located above the restroom was used as a second form of heat exchanger. Energy is transferred from the warm water to the air and that air is diffused to increase the temperature. In turn, this cools the water and the cycle continues.

Once the temperature in the restroom is at its desired temperature, the water is redirected to an indirect water heater where the warm water is used to wash dishes or other warm water applications. Water temperature increased 12 degrees Fahrenheit after the pump installation.

How Does it Work?

A four-branch manifold and two zone values together create a pump. This allows the system two switch between two different water lines. A zone controller monitors the zone temperatures with a thermostat which determines what value needs to be running.


Subassemblies were created for faster installation. A restroom heat exchanger subassembly and a condenser heat exchanger manifold subassembly were both used in the Herd & Horns heat transfer project. With the design completed the team installed the subassemblies through a two foot opening in the ceiling.  

Herd & Horns saw major improvement with their energy consumption and operating costs after this Heat Transfer project was complete. To learn more about the mechanics of this project, visit https://www.youtube.com/watch?v=CQXG9WJAp3k&feature=youtu.be