Browse Forums Heating, Cooling & Insulation 1 Dec 10, 2008 9:08 pm Hi
I am trying to make a decision on installing a solar hydronic in-slab heating system in a new house which I hope to build in 2009. I'd also like to install a solar hot water system. I believe that I will require a back-up system and am wondering about either LPG, electric or heat exchange. I'd also like to have solar panels for electricity provision. I need to make final decisions on the system type so that the architect can make the appropriate designs for the roof trusses. I have been advised that should tanks be required in/on the roof then the trusses may need to be strengthened, depending on the system chosen. I seem to be going round in circle with my own research and would love to get the decisions finalised. Can anyone give any suggestions or contact details for anyone, or any company, who could help me with this. I'm about an hour north of Melbourne. Cheers Catherine Project New Home VIC 3442 Re: Solar Hydronic Heating and Hot Water System 2Dec 10, 2008 9:27 pm Catherine Hi I need to make final decisions on the system type so that the architect can make the appropriate designs for the roof trusses. I have been advised that should tanks be required in/on the roof then the trusses may need to be strengthened, depending on the system chosen. I'm about an hour north of Melbourne. Follow the recent thread on: https://forum.homeone.com.au/viewtopic.php?t=11755 Personally I think you save your $$$s and built a house with good orientation to the sun and heat the slab directly through the north facing windows. Insulate well and you can forget about hydronics. It will be more effective and cheaper. I would only go with hydronics if you can't get the sun into your house or had the desire to get floor heating to every corner of the house. You will still need to get sun onto the roof. Accept that you can't get more than 40% heating efficiency from the sun using a solar collector. A solar hydronic system can set you back about 15K or more! Expense wise for boosting: Wood < Natural gas or Solar or Electric heat pump < Electric water heater or LPG The trusses may need strengthening but not as much if you had the tank sitting on the roof. You would use a split system (tank on the ground) if you were using the solar hydronic option. Re: Solar Hydronic Heating and Hot Water System 3Dec 10, 2008 9:29 pm We wanted to do this as well, however the expense and lack of people who knew about it meant we saw it as high risk without any economic benefit. From memory it was going to be over $20,000 and you still have to cool in summer! Its a great concept so I would love for it to work out for you. We even thought of just putting pipes in the slab for later, but this was also expensive
regards sean Re: Solar Hydronic Heating and Hot Water System 4Dec 12, 2008 8:58 am Thank you both for your replies. I really appreciate everything I can gather to help me make the best decision.
In terms of orientation, the house has the living and kitchen area (which will be a busy place!) facing north, however there is one side of the house that will not warm through passive solar at all as it faces south. I will try to attach a basic house plan if you're interested. The house will also have a verandah around it which will essentially block a fair amount of passive solar in the winter but more importantly block the summer sunshine. The house will be fully double glazed and appropriately insulated, likely minimums of 2.5R in the walls and 3.5R in the ceiling. Our climate is very cold a lot of the time hence the desire to have a substantial and comprehensive heating system. I believe that building on a slab will negate the need for any cooling system. There are only a few days a year that the heat here is horrific in the non-insulated cardboard box we currently live in so I am happy to forego aircon. Ceiling fans should be more than sufficient. In terms of heating, I'm not keen on ducted systems at all. I see in-slab hydronic heating as a lovely alternative with a beautiful heat that should keep the house at a fairly constant temperature. I'd also consider using hydronic heating with radiators throughout the house but am quite keen on a slightly warm floor. We have access to wood supply and had wondered about having a coonara as the booster system. Sometimes in summer it can get very cold and we thought that having a coonara in the living area might allow relatively instant (when compared to in-slab heating which would be switched off during this time) centralised heat. Also, in the winter, if we had the in-slab on to get above freezing in the house, the coonara could be used to give a boost to the heating rather than dialling the in-slab temperature up. Does this make sense? The cost of having in-slab heating is considerable, especially if you try and couple it up with solar. It is a huge outlay but I guess I hope that the cost is at least partlally offset by lower future electrical bills, and I do keep hearing that electricity is only going to get more and more expensive. I'd love to speak to a heating engineer who doesn't have their own specific product to sell but who advises on the options and which one could be the best for my home and location but so far all I've found is product sellers, who understandably think their product is the only solution. Any suggestions? Catherine Project New Home VIC 3442 Re: Solar Hydronic Heating and Hot Water System 5Dec 12, 2008 9:30 am Catherine the living and kitchen area (which will be a busy place!) facing north, however there is one side of the house that will not warm through passive solar a verandah around it which will essentially block a fair amount of passive solar in the winter but more importantly block the summer sunshine. fully double glazed and appropriately insulated Our climate is very cold We have access to wood supply and had wondered about having a coonara as the booster system. The cost of having in-slab heating is considerable, I'd love to speak to a heating engineer who doesn't have their own specific product to sell Are you committed to the design yet? Another way of getting solar into the southern side is by changing the roof line and using clerestory windows facing north. If you design your north eaves right than you can get passive solar winter and exclude summer sun. They don't need to be that deep on that side. The west and east is where you get low sun. The west side is particularly bad in the hot afternoon. Other passive solar considerations is minimising windows on those aspects. We installed a radiant barrier in the walls as well to prevent summer overheating. If you really have cold winter pushing the R value another 0.5 may be useful. The double glazing will help (get good ones). If you keep sleeping quarters and utility room on the south side you can reduce heating requirements. We sleep cooler anyway. Havign a wood heater with a wetback is a good combination to provide central and space heating. Have you got good access to wood? The cost of hydronics is expensive. I don't think you will ever be likely to recoup the cost in energy savings (but who knows what energy prices will do - if we go nuclear , prices probably won't jump much at all). But if there is no alternative than wood, natural gas, solar (or in another thread - heat pump) are your best hydronic boosting options. Try contact AIRAH about finding an independent assessment. http://www.airah.org.au Does anyone have a suggestion for a good hydronic in slab heating speacialist who may be able to help me with an existing system and wether or not it may need a seperator… 0 4882 the sun master is the solar heating to "warm" the water in the tank the S26 is your hot water system which will heat the water (25 degrees?) so with both turned on you… 2 13568 I want to build a decking to the drawn shape outlined in black. The problem is how close can I build to the gas hot water unit? Will I be able to build around it and be… 0 20224 |