2022 RETA Breeze Nov-Dec

SERVICE

The Shade Tree Mechanic volume XLVIII

Emergency Condensing, Part 1

condensing temperature as low as we could get it. There was no way to get lower enough to cause issues. There was no reason to ever allow the pump to shut down. Now in all honesty the pumps weren’t going to cycle off anyway. But he wanted the operators to know that if water flow stopped for any reason, they needed to tell him. Cold water is good. Can we get the water colder? Well the water supply temperature is fixed by God. You can pray, but I doubt he’s gonna answer this one. So we looked at sump temperature. It was higher than make-up water temperature by about 18 degrees. So we turned on the makeup water, full on. Makeup water over the coils, and then down the drain. I told you it was going to be expensive! This gained us a lot of that 18 degrees. A little help and he needs all he can get. We looked at the idea of possibly lowering the temperature further by putting ice in the sump. Unfortunately, the only ice maker we had was on the same ammonia system. So we would not gain anything. The heat to make the ice would have increased the discharge load. So this would have been a wash. If he had had an ice maker or another system or a standalone ice maker, I would have suggested using ice during peak loads if needed. Next we looked at surface area. Water on surfaces helps heat transfer, If you’re looking at RETA Industrial Refrigeration Book 1, this is heat transfer by conduction (See Jim, I remembered that!).

What if we could increase the amount of surface area that had water contact? We would increase capacity. So cleaning the water supply and distribution system came next. Every nozzel needed to be function ing, strainers clean, that broken end cap replaced. We needed to make sure all of the water from his pumps was getting to the coil and distributed to get maximum capacity. A little help and he needs all he can get. Then we jumped outside the box. We was think’n real thinkin, not just beer thinkin. So let me explain how this condenser worked. Water sprayed from the top down through the coil. The fan was on top, so it was drawing air through the coil as well. What if we could spray the bottom of the coil as well as the top? We decided to put sump pumps in the sump and spray up- ward. The bottom of the coil was mostly dry, so why not get it wet and try to in- crease capacity. This was really simple, a trip to Menards for a very cheap sump pump. Then to the garden center for garden hose spray nozzles. He attached the spray nozzles to the outlet of the sump pump and sat the pumps in the sump. They did a great job of wetting the bottom of the coil. A little help and he needs all he can get. Next time, we’ll look at air and load. The shade tree grows outside of the little town of Broughton, Ohio. Where everyone is always welcome, the beer is always cold, and something is always needin fixin.

So’s he comes runnin into my shop. “Man this condenser is uglier than my ex-wife’s mother. But with supply chain issues it’s gonna be six months before I can get a new one. What can I do to keep running until this thing can be replaced? I need about 25% more capacity than I got and I can’t risk blowing a hole in it.” Now this is some real shade tree mechanic stuff right here. So’s I walked over to the friginator and grabbed a couple of beers. We headed outside and commenced to talkin. First thing we ruled out was cleaning the condenser coil. Giv’n the pictures he showed me, for the first time in my life, I considered white rust and scale his two best friends. So what can you do, when you can’t do nuthin? Well if your going run production you got to do something. Chances are anything you do is going to be temporary and expensive. If it’s a matter of running production or watchin paint dry, we’re gonna run production. When attacking condensing, there are three areas to go after.

1. Water 2. Air 3. load

So we started discussin water. Water is our friend. Quantity and temperature. We elimi nated the idea of pump control. We turned the water pump full on and drove the

RETA.com 15