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Last month I wrote about how we cut our natural gas consumption over the past winter by 26 percent. This month I’ll elaborate on how we did it and give you the worksheet we used. But first we’ll have to review last month’s article a little.
With predictions that the cost of natural gas would double over the winter of 2005-2006, we took a proactive approach and worked hard to keep consumption down. From October to March, we cut consumption from 10,216 therms to 7,576 therms.
The predictions were close — the price per therm almost doubled, from $.68 to $1.12. And even though we used 2,640 less therms, we paid $1,508 more than the year before. Without the cuts, our bill would have been another $2,991.
The strategy was to teach employees how the system works, set guidelines for when the floor heat should be used and monitor the system daily, sometimes even hourly.
The worksheet we used can be found on the sidebar.
The thermostat we talk about setting is in the line for the floor heat and measures the temperature of the glycol as it returns from the bay, before it reaches the boiler. The thermostat will ignite the boiler (or, as I like to say, burn that expensive gas) if the glycol is below the set point. The lower the set point on the thermostat, the less the boiler will burn our money (gas).
If you can lower the thermostat set point by watching the temperature of the bay floors, you can save on gas.
The nighttime settings for the different forecasted temperature ranges were arrived at by experimentation over the first two or three months.
At first we thought we could set the thermostat at 50 degrees or so and it would work regardless of the degree drop overnight. We found out rather quickly that the colder the overnight temperature, the higher the set point had to be. It makes sense now.
In order to measure the temperature of the bay floors we bought a hand-held, infrared temperature sensing device. Simply point the red dot at the object you want measured and, “Presto!” there it is.
We took the temperature of the bay floor at the same place in each bay, about four feet from the front, in the center, before the pit.
Interestingly, we found that the bay floors hardly ever had ice on them until the floor temperature was below 21 degrees. I don’t know why. We tested the infrared sensing device on ice water and it read 34 degrees, a couple of degrees higher than what it should.
We kept track of the temperatures, forecasted and actual, in order to have a record and to analyze what went wrong in the event something happened. We recorded the local newspaper’s forecast to test its accuracy and dependability (not good).
The thermostat setting for bays 1-6 and 7-12 are different. When we built the new bays (7-12), Huron Valley Sales told us we would have less heat loss if we installed insulation pads under the concrete floor. We did and I believe Herm, our contact at Huron, was right.
We also tried shutting down some of the bays overnight, or during extremely cold weather. This was abandoned after a couple months for lack of proof it was saving anything and concerns that customers might think that the carwash was totally closed.
Overall we were pleased with the results, we saved almost $3,000 at minimal cost and more important we proved that it can be done. I don’t expect the price of natural gas to go down any time soon so this will be a yearly project.
There is one additional benefit that I forgot about until writing this article. When I talked to Herm, he told me of a way to save 16 percent on the cost to heat the water. He e-mailed me the information, I printed it and deleted the e-mail. But when I looked at the printed sheets, I couldn’t read it. It looked like Chinese.
So that’s my next project, if Herm will resend it to me.