Hydronic Heating And Cooling?

 
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Old 06-01-2017, 09:01 PM   #1
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Hydronic Heating And Cooling?


We're involved with a project that is going to have ICF walls, concrete floors on the ground level, not sure what on the 2nd. The owner is well heeled and wants to do something environmentally friendly. He was asking about hydronic heating and cooling.

I'm somewhat aware of hydronic heating, know it's a proven technology but not much more than that but haven't really head of hydronic cooling, did some research and it does exist although there were a lot of cautions about using it. The most informative article I found on it was for commercial applications and said that it was imperative to have sophisticated sensors and a dehumidifying system that runs on automatic controls to avoid condensation problems.

I posted the question on a forum that deals with energy analysis and reports and a couple of engineers came back with a warning to be sure and have the E&O policy up to date, another one said they've done it with no problem.

Now we're thinking of going with a radiant system in the floor for heating only and maybe VRF mini splits for the cooling but are still open for the cooling if we can find a good system. There was another article that said there are aluminum panels that hang from the ceiling that are designed for hydronic cooling and that sounded interesting as cool air sinks and it would be possible to maybe put blowers over the panels?

What's the good, the bad and the ugly on this?
Thanks,
Rio
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Old 06-05-2017, 05:36 PM   #2
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Re: Hydronic Heating And Cooling?


You should google "passive chilled beams". I've never seen them in a residential home, mostly in large commercial applications.

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Old 06-07-2017, 09:13 PM   #3
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Re: Hydronic Heating And Cooling?


Thanks Bicey for the info, looked into passive chilled beams and they look indeed like they are for larger commercial projects, got some info on the below which looks interesting.

Messana Radiant gypsum technology uses A high performance RADIANT DELIVERY SYSTEM for residential and commercial buildings. Hydronic distribution systems use water to move energy from where it is produced to where it is needed through a small circulator pump, reducing energy use and allowing an optimal distribution of heat.
The hot water (in the winter season) and the cold water (summer) generated by the heating and cooling source (typically heat pump or a combination of boiler and chiller) is conveyed through an innovating press fittings technology and piping system to the active ceiling panels (Ray Magic gypsum panels) that in the winter deliver heat to the room and in the summer extract the sensible heat through the chilled ceiling.


Got that info from an engineer who used these panels in a couple of high end homes up in northern Cali, he also said to make sure your E&O insurance was current if you go that route.

As mentioned up the thread we're leaning towards radiant heat in the floor and a couple of VRF mini splits to provide cooling and ventilation; this way there are no ducts, the minis are very energy efficient with SEERs in the high teens, if the radiant breaks down there is still heat and from talking to a couple of mechanical engineers radiant cooling is so expensive it will probably be cheaper to have two separate systems rather than the one elaborate radiant combination.
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Old 06-08-2017, 01:12 PM   #4
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Re: Hydronic Heating And Cooling?


If you're building a high efficiency home, well sealed and well insulated, what are you doing for ventilation? All the high efficiency homes here have an HRV/ERV which require duct work anyway.

A little technical rant, I try not to interchange the terms "hydronic" and "radiant". Hydronic is just the method of transporting the heat. You could have a hydronic heating system that just flows through coils in an air handler system, so forced-air hydronic...but not radiant. Radiant is is just the way the heat is realeased to the room.

Regardless of the heat transport mechanism or the way it is released into the room neither makes a system and more or less energy efficient, just the heating source. If we're talking gas fired then I would argue that in general that the condensing forced air furnaces tend to be able to achieve higher energy efficiency ratings and the electrical energy used by the fans is less than the pumps of a boiler based system.

There are air-to-water heat pumps that can be used that would be more efficient than gas fired, but I'm doubtful they are more efficient than their more common air-to-air heat pumps.

I'd rather not get into the geothermal angle...but my stance is they are mainly bunk science.


The only reason I would choose radiant hydronic heat is comfort...and damn is it is comfortable! Nothing like waking up to warm floors or wall radiator. You can also zone it quite easily compared to forced air so more control.

The downside to radiant hydronic heating is the cycling time. It takes a long time to warm up and cool down in relation to changes in the thermostat. So if you're only periodically heating it can be quite annoying. Take a detached shop for example that you only want to heat on a few cold days of the years, or for a couple hours to do something. You have to turn the heat on many hours in advance to for the heat to radiate into all the mass to warm the room up. This is where you can lose a lot of efficiency in that a radiant hydronic system will have to run a lot longer to achieve the same air temperatures and a forced air system. Up in the mighty north here, our heating systems are running all winter long, so it's not much of a problem, but when you start getting into mixed climate.

I'm not against radiant hydronic heating, I just haven't found any evidence that it is more energy efficient (like what a lot of the marketing literature would have you believe). The only argument where it might be true is if the house is zoned and you keep some areas of the house cooler.
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Old 06-10-2017, 02:43 PM   #5
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Re: Hydronic Heating And Cooling?


Thanks for all of the information Philament; They're required to have an IAQ (Indoor Air Quality) fan of some sort, might end up with a whole house attic fan, the property is in San Diego which has pretty good weather all year so not sure if they're going to go with an HRV/ERV although that is a possibility.

Thanks for the heads up regarding the potential difference between hydronic and radiant, good point on that, in this case it's hydronic radiant heating and possibly cooling.

I'm not sure of what they're going to using as the heat source, I'm working with a designer friend and associate on this project, he's the one who is in direct contact and control of the project. I suggested to him to use the services of a really competent plumbing/heating/Cooling contractor I've worked with on numerous projects or possibly a mechanical engineer, was really getting preliminary information on it per his request.

I was on another forum I frequent that has to do with California energy efficiency compliance and one of the engineers on there was touting air to water heat pumps but said there was a problem with getting them into compliance with state regs, for now nothing has been decided in that department.

Regarding geothermal heat pumps I'm surprised that you think they're bunk science, it would seem to me that especially in areas that have large temperature fluctuations that having a constant 55 or 60 degree reservoir for the heat exchange would make a lot of sense. What don't you like about them?

I agree that the big advantage of hydronic radiant heating is the comfort factor, the point about the long lag times is one to definitely keep in mind, I've also read that with radiant heating one can be comfortable with temperatures that are lower than one would normally use.

Thanks for taking the time to go into the subject a bit, appreciate it and I'll pass this on to my comprade for digestion and discussion.

Take care,
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Old 06-10-2017, 07:07 PM   #6
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Re: Hydronic Heating And Cooling?


Quote:
Originally Posted by Rio View Post
I was on another forum I frequent that has to do with California energy efficiency compliance and one of the engineers on there was touting air to water heat pumps but said there was a problem with getting them into compliance with state regs, for now nothing has been decided in that department.
It's been 5 or 6 years since I was deeply involved in my research for air source heat pumps, when a few Japanese companies were starting to try to sell the air-to-water heat pumps (daikin altherma was the one I was looking at) into north america and at that time they couldn't be imported because there was no test for them. They didn't technically fall under the scope of the federal heat pump and air conditioner test method (10 CFR Appendix M to Subpart B of Part 430 maybe in the US??). They were really cool though and had a lot of promise. The US is probably similar, but there are a lot of provinces here where electricity is much cheaper than gas and many places only have propane or oil as an alternative to electricity for heating. So I was pretty keen to see this technology being introduced as a replacement for a lot of the oil-fired boiler systems.

As to the radiant cooling part, these types of systems are very tricky to engineer. They have to be accompanied with dehumidifiers to regulate the relative humidity to combat condensation problems. I will admit they are not my strong point, but they seem very new and untested in the residential market. As evidence, here's a video from Matt Risinger posted just a few days ago about an experimental system his HVAC engineering company just installed in their office. If even he is leery about putting one in his homes with all of his resources, I would be inclined to go a different route for cooling



Quote:
Originally Posted by Rio View Post
Regarding geothermal heat pumps I'm surprised that you think they're bunk science, it would seem to me that especially in areas that have large temperature fluctuations that having a constant 55 or 60 degree reservoir for the heat exchange would make a lot of sense. What don't you like about them?
They are essentially site built hvac systems that cannot undergo the same rigorous testing that conventional packaged HVAC equipment does so a lot of their efficiency values are speculative through unaccounted for losses and there was some research (can't find it now) that suggested they decreased fairly significantly in efficiency over time. The actual equipment in the house is extremely expensive with a short lifespan (10 years last I looked??? and they're maybe 10-15K). Not to mention they're about the least serviceable HVAC equipment if anything goes wrong. Saw one homeowner that had to dig up their whole yard and redo the piping because of a failure after a few years...~15K job....after they had just done all their landscaping.
Here's a study that monitored them https://www.hydro.mb.ca/regulatory_a...ppendix_38.pdf
The actualized numbers aren't very impressive. I just don't see them as being any better than the air-to-air or air-to-water heat pump technology for single family dwellings, but have significantly greater startup and maintenance costs.
And if you think about it from a 50000ft view, the vast majority of people in the world live in densely populated areas so the research money is going into developing more efficient systems that will work there as well as single family homes like air-to-air and air-to-water heat pumps.

On a community/commercial level, I can see some possible benefits.

If you want to see a really cool HVAC system, check out the Drake Landing Solar Community project, now that's one ingenious system of using earth thermal storage for solar energy.
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Old 06-12-2017, 10:27 PM   #7
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Re: Hydronic Heating And Cooling?


I know that a couple of years back an air to water heat pump was being mentioned as a work around to get electric water heating as there is such an energy penalty under Cali's Title 24 Part 6, which is one of the mechanisms being employed to push our 'greenhouse gas emmissions' to 40% below what is estimated we were producing in 1990; I'm all for being energy efficient but would definitely be pursuing this in other manners not the least of which is letting the amazing advances in energy technology of all sorts come forth; in other words having a little patience. The efficiency's on some of these VRF mini splits is terrific, SEERS in the high teens to twenties, of which currently in Cali only the efficiency of 14 SEER can be used when modeling.

That was a really nice video, explained the radiant well. It's so interesting how it transmits through the air and heats the body directly without having to warm the whole structure, haven't really been around any, including radiant heating with radiators so it was an eye opener, and yeah, from the little I've been reading on the subject it sounds expensive to do right. Automatic sensors with automatic controls, but not automatic troubleshooting to any extent I warrant.

Thanks also for your take on geothermal systems. It seems funny that the heat sink would deteriorate over time it that was what you were referring to, seems like with schedule 40 PVC or whatever they're using it would be stable and the earth's temperature isn't changing at the depth they're using; The 10-15k for 10 years of service is way too high, that's almost $100 a month just to budget for a new system! Ouch!!
If we ever go in that direction I'll certainly keep what you wrote in mind and will have a more skeptical sense regarding these systems going forward.

I found your observation on how much more the technology is involved with direct air to air and air to water heat pumps due to the compact nature of them and the way most of us live to be very persuasive and a cogent observation, one that's backed up by how fast these systems are developing

Thanks for taking the time to answer the questions and I'll post up what we end up doing on this project as it advances.

P.S. Am going to check out the DLSR Community project pronto!

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