Hello Guys! It has been a while since I have been on here. The house, 4100 sq feet north of Houston, TX is working great. We have been in it three years now and all is well. I have just put up a barn and had a deep spring fed pond built. The barn is 2000 sq feet sheet metal, 16 foot walls, 3/12 pitch. It has (2) 12x14 doors and (1) 12x12 door and 2 man doors. The building will be spray foamed and more than likely have a large 14 ft ceiling fan in it. I have a manual J heat load calculation, but it is a little misleading. I am attaching it to this post. It calls for 2.27 tons of HVAC, but I do not think that this will work as I want to use it. The goal of this project is to keep the building around 85 during the summer and control humidity somewhat when the building is not being used. It is basically a shop for me... When I want to use the building, I want to be able to cool it down rapidly to about 70-74 and maintain that temperature while using the space. That being said, I am leaning towards a 4 or 5 ton unit with pond loops. I do have a professional pond loop installer that has been doing this for over 30 years. He will put whatever I want in the pond and the pond is 20-30 ft deep and about 1.3 to 1.5 acres in surface area. I still need to measure the new pond for accurate area. What are your thoughts. Doc? Anyone...? Has anyone done this type of installation before? Pics below with manual J attached.
Sure..put a pond loop in, which should allow for low water temps in Texas Climate..... If you want rapid response, you need more capacity. If you oversize too much, you don't get good humidity control, since it will not have a long enough runtime. At least dual stage if not variable speed equipment should be beneficial in that case.
Open loop optional, as I have a new Well that flows about 58 gpm but the water is hard, around 154.238537009 ppm of hardness. The pump is 5hp. I am concerned about hardness and pump longevity. Doc????
What happened to the pond? I assume you will not use a 5 HP pump to feed water into your heat pump? Hint: very inefficient pumping. I am usually not a big fan of open systems, unless you have not much choice, due to water quality issues and higher pumping power. But in Texas climate, open systems stay relatively cold, which is good. Just make sure you select a pump which operates efficiently. Might have shorter lifespan of the geo well pump due to water hardness.
I have installed a lot of pond loops in the Houston area, and my only issue is that the few days we get 15 degree cold snaps they sometimes operate right above freezing, and can trip out on cold water. You can add antifreeze, or if there is enough horizontal ditch between the pond and the home it may not be an issue.
Add some antifreeze if needed. Keep in mind, up to 39F water temperature, the coldest part is the bottom of the pond. Below 39 F, the bottom becomes the warmest part.
Plates for the pond? Keep in mind that the plates are overrated, meaning that the capacity is much less then they state. E.g., out of a 5 ton plate heat exchanger, you get not more than 2.5 ton capacity out of it. At least that is our experience. Best way to deal with heat rejection (and extraction) it is a slinky tied to a PVC frame and cinderblocks, with UV resistant wire tiers. http://welserver.com/WEL0384/ is an example.
