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I have a couple of questions for the group in connection with a sizeable addition project in Minnesota. (the addition is approximately 2400 square feet).
b Background.
We are installing hydronic heating in the addition. The total heating load for the first and second floor is approximately 62,000 Btus. Most of this is addressed with ½” PEX in Warmboard, and the rest is addressed with radiators. Water will run through the tubing and piping for these levels. Most of the Warmboard will be installed under hardwood floors (standard 3/4” oak) so the water temperature will need to be kept quite low for these areas. I am also looking to put something in the 140 degree neighborhood into the radiators to achieve optimum efficiency.
The garage is a tuck-under (under the first floor), and we are installing hydronic tubing (again ½” PEX) in the slab for the garage as well as the adjacent storage room and mudroom. The total heat load for this “lower level” is approximately 23,000 Btus. Water will run through the tubing for this level.
We are also installing hydronic tubing in the driveway. A glycol solution will run through the tubing here. We do not plan on using the snowmelt system much (we can certainly benefit from the manual labor snow shoveling provides), but given that the driveway slopes into the house, we thought it best to get some help via heat in the event of icy conditions so we do not take out the garage door. The heating load for the snowmelt system is approximately 127,000 Btus.
After the addition, we will have two full baths, one ¾ bath and one ½ bath. The tub in one of the full baths is a “whirlpool” variety that has an approximately 90 gallon capacity. (The tub for the other bath is a relatively shallow “regular” sized tub). There will be two adults and three young children (children all girls) who will be living in the house.
b Queries.
Here are my questions:
1) I would like to come up with the most energy-efficient, reliable and yet economical system possible to provide the needed heat. It also is important to remember that I am not looking to obliterate the snow as it falls – I plan on shoveling and only using the snowmelt sparingly. I am considering using an MZ low mass boiler distributed by Monitor Products. What are people’s thoughts on that boiler (and on low mass boilers in general)? The concept seems to make a lot of sense to me (sports car vs. truck analogy, etc.).
2) I have also been considering a Polaris hot water heater in lieu of (or perhaps in combination with) the MZ. What are the thoughts on this? (The Polaris unit has a 50 gallon tank and approximately 100,000 Btus.
3) Would it be workable to rely on the MZ (say the 94,000 Btu unit or the 142,000 Btu unit) to heat the house (1st and 2nd floors and lower level)? Could I also effectively use the MZ unit to handle the snowmelt and the house (on the rare occasions when it would be used) and alternate between the house and the snowmelt using a priority switch? Would the best way to do this be by running the glycol for the snowmelt through an appropriately sized plate and frame heat exchanger. (The HVAC contractor I am working with is concerned that a heat exchanger will not work appropriately).
4) Would it make sense to try to get even more “bang for my buck” by attempting to use the MZ to provide the heat for potable hot water? Would the best way to do this be to utilize an indirect hot water heater? What brands would be best here? My sense is that the Ergomax tends to work best with real hot water (i.e., around 180 degrees) and that it would not be the most efficient for me to heat that high given the amount of mild or warm water I will need).
5) Alternatively, would it be more efficient and/or more prudent to simply go with a separate power-vented or sealed combustion hot water heater for the domestic potable water? As intimated above, is there a way where I could combine the MZ and the Polaris effectively to address the hydronic needs in the house, the snowmelt and the domestic hot water (again, perhaps through the use of heat exchangers and/or indirect tanks)?
Please let me know if additional information would be helpful or if you have recommendations as to other contacts or resources to explore this with.
Replies
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Check out http://www.rap-info.com
*You may also want to check out the discussion forum at "Dan Holohan's Wet Head" web site as it is dedicated to questions regarding heating problems. It is at:http://www.heatinghelp.com/wall_forum.cfm
*I think "Skip"(Query) is every Mechanical Contractor's worst nightmare. If I was in the medical profession and had a patient present the same parameter of requirements, I wouldn't have a clue as to which limb to sacrifice first if the core was doomed to failure.[g]The combination of systems, controls and components you are considering is a f**kup just waiting to give birth. The tasks you are describing are realistic and certainly within reach. The "trivialization" or lack of detail you ask us to comment upon is quite disturbing. You need to hire an engineer or radiant designer you have undivided trust in to put together a design that will function as "a system" to achieve your objectives. I would entrust (and compensate) that very same design professional to commission the system and stand behind the operation. Big Bucks, I know. But would you rather have a Heart Surgeon who is doing his first bypass or one who has done his 60th transplant? What will you do with the responses you get from the internet Skip, "guide your mechanical contractor in the right direction"?Knowledge is a good thing. A little knowledge can be very dangerous indeed. Self treatment is a noble gesture, risky at best, many times even a successful outcome. What really concerns me is when the patient consults his "friends", let alone those whom he hardly knows, to assess and diagnose the situation, over the phone or picket fence and then "prescribe" the chemistry and correct dosage.How many square feet in the snowmelt?? 100 sf??? Less or More??? How many BTUH sf? Have you factored the acceleration equation considering the proposed control strategy and your realistic future expectations? I have a buddy who has a cherry Packard in his game room. Of course he lives in a slab on grade in Phoenix and never drives it when it gets below freezing, let alone "downhill" towards his house coming home from work in a climate such as Minnesota.Just wondering why you are fishing? Can't find a competent engineer or specialty systems designer in Minnesota?Jeff(I think[g] I saw your post on an industry forumn earlier in the month and took the time to write a response. Have you had time to read it?)Sorry Skip, I don't want anyone to end up in the wrong end of some type of Tijuana quick fix clinic from a DMSO claim.
*Dear Skip,I am concerned that you need 62,000 BTU to heat 2400 square feet. Are you using any insulation?-Rob
*I have done some research on some hydronic manufactures and would suggest a resource, Radiantdesigninstitute.com. I would collect all of what I thought the heat loads are, then have someone who could stamp prints do the noodle work to verify your findings. The varied heat loads could all be supplied from one heat source, or many heat sources for each job. The 'KISS' school of design would have several heat sources for the different loads. This will cost more, but you will have a less complex system and have some form of heat if one of them chooes the coldest day of the year to quit. In my heating system I will be looking for somthing simple, heat is not something you want to be failure prone.
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I have a couple of questions for the group in connection with a sizeable addition project in Minnesota. (the addition is approximately 2400 square feet).
b Background.
We are installing hydronic heating in the addition. The total heating load for the first and second floor is approximately 62,000 Btus. Most of this is addressed with ½” PEX in Warmboard, and the rest is addressed with radiators. Water will run through the tubing and piping for these levels. Most of the Warmboard will be installed under hardwood floors (standard 3/4” oak) so the water temperature will need to be kept quite low for these areas. I am also looking to put something in the 140 degree neighborhood into the radiators to achieve optimum efficiency.
The garage is a tuck-under (under the first floor), and we are installing hydronic tubing (again ½” PEX) in the slab for the garage as well as the adjacent storage room and mudroom. The total heat load for this “lower level” is approximately 23,000 Btus. Water will run through the tubing for this level.
We are also installing hydronic tubing in the driveway. A glycol solution will run through the tubing here. We do not plan on using the snowmelt system much (we can certainly benefit from the manual labor snow shoveling provides), but given that the driveway slopes into the house, we thought it best to get some help via heat in the event of icy conditions so we do not take out the garage door. The heating load for the snowmelt system is approximately 127,000 Btus.
After the addition, we will have two full baths, one ¾ bath and one ½ bath. The tub in one of the full baths is a “whirlpool” variety that has an approximately 90 gallon capacity. (The tub for the other bath is a relatively shallow “regular” sized tub). There will be two adults and three young children (children all girls) who will be living in the house.
b Queries.
Here are my questions:
1) I would like to come up with the most energy-efficient, reliable and yet economical system possible to provide the needed heat. It also is important to remember that I am not looking to obliterate the snow as it falls - I plan on shoveling and only using the snowmelt sparingly. I am considering using an MZ low mass boiler distributed by Monitor Products. What are people’s thoughts on that boiler (and on low mass boilers in general)? The concept seems to make a lot of sense to me (sports car vs. truck analogy, etc.).
2) I have also been considering a Polaris hot water heater in lieu of (or perhaps in combination with) the MZ. What are the thoughts on this? (The Polaris unit has a 50 gallon tank and approximately 100,000 Btus.
3) Would it be workable to rely on the MZ (say the 94,000 Btu unit or the 142,000 Btu unit) to heat the house (1st and 2nd floors and lower level)? Could I also effectively use the MZ unit to handle the snowmelt and the house (on the rare occasions when it would be used) and alternate between the house and the snowmelt using a priority switch? Would the best way to do this be by running the glycol for the snowmelt through an appropriately sized plate and frame heat exchanger. (The HVAC contractor I am working with is concerned that a heat exchanger will not work appropriately).
4) Would it make sense to try to get even more “bang for my buck” by attempting to use the MZ to provide the heat for potable hot water? Would the best way to do this be to utilize an indirect hot water heater? What brands would be best here? My sense is that the Ergomax tends to work best with real hot water (i.e., around 180 degrees) and that it would not be the most efficient for me to heat that high given the amount of mild or warm water I will need).
5) Alternatively, would it be more efficient and/or more prudent to simply go with a separate power-vented or sealed combustion hot water heater for the domestic potable water? As intimated above, is there a way where I could combine the MZ and the Polaris effectively to address the hydronic needs in the house, the snowmelt and the domestic hot water (again, perhaps through the use of heat exchangers and/or indirect tanks)?
Please let me know if additional information would be helpful or if you have recommendations as to other contacts or resources to explore this with.