Conclusions > Recommendations
 Suggestions for the Berkeley YMCA

Recommendations for the YMCA

We recommend that the YMCA install two heat exchangers to recover greywater waste heat.

Residential and Women's Fitness Center Showers

To recover the heat from the residential showers and showers in the women's fitness center, we recommend a vertical-drop, counter-flow heat exchanger. This could be used to pre-heat water going to the boilers in the 1910 building, or preheat fresh water going to the deep pool water heater. This heat exchanger could be installed in the first floor or the basement of the building. At this point, it is unclear how much plumbing this would require. Routing the heated water leaving the exchanger to the deep pool would minimize the amount of piping required, but there may be a larger flow of water to the boilers for the showers in the building.

Commercially available counter-flow heat exchangers like the GFX system cost roughly $1,000 uninstalled. If installation were to cost another $3,000, the system would be less than six months.

Basement Locker Room Showers / Sump

To recover the waste heat from the basement locker room showers, we recommend that a heat exchanger be installed in the sump tank adjacent to the new lap pool. Because the sump is in the same room as the pool heater, a minimum amount of plumbing and building renovations would be required. While we're unaware of any commercially available heat exchangers that are designed for sump tanks, we believe that a system could be built easily. By diverting the cold water entering the pool circulation system through a ½ inch copper pipe which loops several times in the bottom of the sump, the incoming cold water could be raised almost to the pool temperature.

However, we have two concerns. The flow of cold water to the pool may not be large or consistent enough to take full advantage of the warm water entering the sump. One possible solution is to create a slightly more complicated system that would warm the fresh water going to the whirlpool and steam room as well as the lap pool. The second has to do with the safety of running the fresh water through tubes in the sump. There may be regulations governing this.

We estimate that to create and install this system would cost around $2,500 (hiring a plumber for about three days and the cost of 100 - 150 feet of ½ inch copper pipe and connectors). At current energy prices ($1.28 therm), this system would have a payback period of about two months.

Greywater Heat Recovery in Sump