The mystery of rain in an ice arena
Watson: When you gave me an example of how humidity was brought under control in a Natatorium (Indoor Pool) Read the blog, with the side benefit of reducing the energy costs 50%, you said you had a similar experience in an Indoor Ice Arena where the humidity got so high it was actually raining on the ice. Tell me more about that project.
Holmes: Harry was the mechanical contractor who had been trying to fix the humidity problems in the Ice Arena. As a result of his changes, the problem had gotten worse; it was raining on the ice and the electric bills had more than doubled. When we were hired by the Parks Department to fix the problem, our first step had been to install an Energy Monitoring System.
After I told Harry we were going to turn off most of the equipment he had been running, he called the Chuck, the Director and told him, “You can’t let Holmes do what he wants to do. He is going to destroy your facility.”
Watson: That was a pretty nasty thing to tell the Director. What did Chuck do?
Holmes: Harry wasn’t known for his charm. He was a real S.O.B. who terrorized a lot of people in the building industry in that town for about 50 years. Chuck scheduled a meeting at his office.
The three of us sat down in a conference room and Harry started to give me hell saying all kinds of things about me, my work and my Mother. He said any idiot knew that to dehumidify a problem area you had to run all of the air conditioning equipment continuously and that was what he was doing. And to keep it from getting too cold, he had turned on a 100 KW electric heater in one of the rooftop units. Sure it was expensive but there was no other choice.
I knew better and fortunately for me, so did Chuck.
Watson: How did Chuck deal with Harry?
Holmes: He told Harry, “Bill designed that heat recovery system and it worked perfectly for years. It cut our utility costs by half and allowed us to keep the rink open. Read about the original project But I think he is the only one who actually understands it. Over the years, people have kept changing things until its gotten to the mess it’s in now. It couldn’t be much worse, so what do I have to lose by trusting him again. You haven’t been able to fix it.” That ended that and Chuck told me to go ahead.
We had already determined what the problems were and what needed to be done to correct them by using the data from the monitoring system along with spending a lot of time on-site; in the machine room in the basement where the ice machines (chillers), pumps and boiler were, with the cooling tower next to the building and on the roof with the four rooftop units.
Watson: I assume that soon as you had the Director’s approval you went ahead and made the changes.
Holmes: You’re right. My engineer and I immediately went back to the rink and shut down the electric heater, shut off three of the rooftop units and dialed the remaining one down to about five tons, as low as it would go. We set the controls for the heat recovery system to dump the waste heat into the rink to keep the air temperature at 55.
There were several humidity sensors in the rink so we had an actual indicator and record of what happened next. The first thing was a stream of water started to run out of the drain of the operating unit. It was starting to dehumidify, to pull moisture from the rink air. That stream of water was really a very good indicator that things were working right. By keeping an eye on the monitoring system in the rink from my computer at home during the evening and from the resulting reports, I could see that the problems were clearing up much faster than I had expected. It was exciting. The humidity had started out in the mid 60’s. By morning it had dropped to 48%, almost a twenty percent reduction in about twelve hours.
Watson: Did it stop raining in the rink?
Holmes: When I went over to the rink early the next morning, not only had the dripping stopped but the boards were already starting to dry out. In a couple of days it was back to almost where it had been 10 years before. There were no stalagmites on the ice; it was smooth. No electric heat was running and the air conditioning compressor load had fallen from about 200 hp worth of compressors cycling on and off to one running continuously, providing five tons of cooling, only five or ten horsepower.
As a result of the changes the annual energy costs were reduced by 67% and the project won a DOE Energy Innovation Award..
Watson: Apparently what every idiot knew about dehumidification wasn’t quite good enough.
Tell us about your experiences, both good and bad with energy professionals, what has worked and what hasn’t. Send us your comments, thoughts and suggestions on how to improve our profession so we can all continue to learn from each other. Thanks – Holmes & Watson.