Building several greenhouses and need boiler ideas

[drumwerx]

My kingdom for 300 days of sunshine per year. Back when I was just a pup, there was a list going around that had Meadville PA as the second cloudiest place in the united states next to seattle washington. It is rediculously cloudy here...

Geothermal and thermal solar are two different animals. Geothermal extracts heat from the earth's crust which maintaints a constant temperature of about 55 degrees. By using hundreds of feet of buried pipe, a few pumps, heat exchangers, and compressors, you heat your home off of the energy stored in the dirt... and a fair amount of electricity. Usually a large investment up front.

Thermal solar is basically just using the suns energy to heat water inside of a thermal solar panel, and then circulating that water to wherever you need it. The thermal solar panels are basically just tubes of water inside a box with a glass face on them. That might be oversimplified, but you get the jist. Like I said, it's relatively inexpensive, especially compared to photovoltaic solar, and it's a good supplement that is relatively easy to encorporate with a wood fired boiler system.

I guess I don't know 100% what you are asking with regard to the water temp. And to be up front with you, I don't know all the mechanics of a greenhouse and what you guys need as far as heating goes. I suppose if you put hot water heat in the benches below your plants, you wouldn't want to have 180 water going through them or you would cook your tomatoes before you get a chance to sell them. Basically, whatever temperature you need the water, you will just temper it or mix it... meaning the supply to whatever zone you are feeding will automatically draw some of the return water from that zone before it goes back to the boiler and mix it with supply from the boiler to keep the water temp down where you want it. My guess is, along with heat in the benches, you would probably want some air handlers as well. You could use the fans on the air handlers to keep the air moving inside when the weather warms up.

Am I the only person not watching the Super Bowl?

cheers

I had seen a item called a trickle down mat that can get water about 160 degrees and is a lot cheaper than the solar panels. I will make one and see what I get on it.

I want to use radiant heat so the root zone is heated and not have any benches. I will be growing hydroponically and therefore the plants will be right on the floor so the radiant heat will help the root zone.

The reason for the water temperatures is to find out what everybody else has for temperatures in their radiant heat comming from the boilers. Then I will get an idea on what is needed in the boiler and what I need for the trickle down mats.

 

[Piker]

Like I said, the boilers should run at least 150. Most folks putting hot water in their concrete mix it down to 120... you get around 30 Btu's per sq foot that way providing you have enough tubing in the concrete... usually 1 foot of tubing per sq foot is what most guys use around here.

It's possible that I am not being that helpful at this point... as I am still unsure of exactly how you want to set this up.

cheers

 

[drumwerx]

Like I said, the boilers should run at least 150. Most folks putting hot water in their concrete mix it down to 120... you get around 30 Btu's per sq foot that way providing you have enough tubing in the concrete... usually 1 foot of tubing per sq foot is what most guys use around here.

It's possible that I am not being that helpful at this point... as I am still unsure of exactly how you want to set this up.

cheers

I want to have the solar panles and wood boiler to keep a water storage system at the correct temperatures to give me the radiant heat the greenhouse will need all night and in cloudy days.

I am not sure of the cost of any of the boilers. What the smallest and largest ones cost would help.

You have helped me answer some questions I had on temperatures. It looks like the boilers can get 150 to 170 degrees. The solar trickle down mats get about the same. So if I have a large water storage system, that can be warmed by both the solar mats and boiler, I should be able to heat my floors and the root zone. Then at night or cloudy days the boiler will kick in to keep that storage system there at the correct temperature. It will still keep heating the root zone at night.

The cost of the mats are very inexpensive so having a lot of them will help build the storage system to a good temperature all of the time when the sun shines. Maybe getting a smaller boiler will work just to get the water storage system to a good enough temperature to stop the plants from freezing and rely on the solar mats to do most of the work. With 300 days of sun a year it is going to be hard to figure what size boiler I will need if the panels do well. I may just start with the panels and see what I get as far as root zone temperature's and inside temperatures and then see what I need with a wood boiler to get the temperatures higher after I build the greenhouse. I will not be able to grow a lot the first year this way. Or if I have the funds just get the largest one they make. The 1,000,000 BTU unit will be more than enough and then if it is way overkill when I expand the greenhouses it will be able to provide the heat for the second greenhouse.

I may also get a propane heater in the loop as an emergency unit in case the wood boiler fails.

So getting an idea on the costs will help on the first one.