Ceridwen I actually used five gallon black plastic pails full of water when I first built the greenhouse. I had a thermometer probe in the water. The pails were placed under the bench facing south. For every one degree rise in a gallon of water it represents 8 BTU's. Once the ambient temperature drops the black pails radiate the heat back into the greenhouse. A five gallon pain raised one degree would give you 35 BTU's. Not a reliable way to heat a greenhouse in a cold climate like mine but it can help. Arnold -----Original Message----- From: Ceridwen Lloyd <ceridwen@internode.on.net> To: Pacific Bulb Society <pbs@lists.pacificbulbsociety.net> Cc: Arnold Trachtenberg <arnold140@verizon.net> Sent: Fri, Jan 8, 2021 3:27 pm Subject: Re: [pbs] Greenhouse: heating and insulation in winter Although we do have electricity to our (glass, roof-vented) glasshouse, the cost of heating it that way would be prohibitive, despite only being zone 9ish with frequent frosts (South Australia has the highest electricity prices in the world.) Under the staging we have placed half a dozen black plastic lidded storage bins (about 60L size) filled with water as temperature buffers, and up one end our compost tumbler to generate a little warmth. It’s on a concrete slab next to a 22,000 gallon cement rainwater tank and one day I’ll work out a way of using the winter sun on the metal tank roof to heat water (like a pool blanket) and exchange it somehow with the greenhouse. Lots of black poly pipe involved (and some sort of Rube Goldberg device!) It’s only single pane 3mm glass so currently has surplus bubble wrap (recycled from my workplace in A2 sized sheets) attached to the insides. I haven’t yet found an Australian source of proper horticultural grade bubblewrap type insulation though have found some in the UK. The problem is photo-degradation. There are no bulbs there currently - one of my kids’ friends is attempting coffee, cocoa, and vanilla - a beverage garden! - with varied success. Ceridwen Sent from my iPhone > On 9 Jan 2021, at 04:21, Arnold Trachtenberg via pbs <pbs@lists.pacificbulbsociety.net> wrote: > > > Here's a photo of the radiant heating system. > For those who aren't familiar this a a typical masonry walled basement here in the NE USA. > The furnace on the left of the picture has a connection to a pump that pushes water to either the greenhouse floor through the red PEX or into the stand by tank for domestic hot water through the copper pipes. > > There is a coil in the tank that transfers heat from the loop to the water stored in the tank. > The large tank is super insulated and keeps water hot for a long time. > There are valves on the return side of each system that controls where the hot water will go. A thermostat in the tank and a thermostat in the greenhouse controls those return valves. > > When either zone requires heat the furnace goes on and the pump sends out hot water. Where it goes depends on the status of the return valves. > > Arnold > > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: IMG_3646.jpg > Type: image/jpeg > Size: 2554592 bytes > Desc: not available > URL: <http://lists.pacificbulbsociety.net/pipermail/pbs/…> > _______________________________________________ > pbs mailing list > pbs@lists.pacificbulbsociety.net > http://lists.pacificbulbsociety.net/cgi-bin/… > Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>
