Airconditiong when you have hydronic heat

GordoG

What is the most popular or common method of air conditioning for houses that have hot water heat? Thanks

SWEI

popular and common

are not adjectives which inspire confidence in me, given the deficiencies in both comfort and value I see in so many buildings.



[/snark off]



Out here in our little corner of the southwest, we like to pair radiant heat with evaporative cooling when we can.  Radiant cooling is tout sweet, but I'm still learning.  Mini-splits are perfect for high loads in tight spots.

Robert O'Brien

Long Island

Airhandler in the attic here by far,hydroair is huge with most newer residential.

The Steam Whisperer (Formerly Boilerpro)

Yes, we (the USA) still are in the dark ages......

and putting in ducted A/C systems.  I recommedd ductless split systems.  Here in Chicago contractors say that they don't work,  et el. , especially for the chruches I've talked to.  From what I understand, all of Asia cools this way. 

SWEI

all of Asia

indeed.  It's not uncommon to see literally hundreds of little outside coils on mid-rise offices and apartments in major cities.

gennady

AC with radiant

installation of residential chiller in parallel with boiler , using same distribution and emitting system is the most logical step, very economical system, but moisture removal system must be implemented as well. I did some designs, but could never sell it. It is not sell-able in USA, as well as cogeneration systems. We are doomed to install atmospheric boilers and ducted relic AC systems. Oil, gas and electricity are too cheap. Forward into the past.

Mark Eatherton

Missed opportunities...

Gordo, Consider this.



In space heating, the cast iron behemoth radiators that are in place are required to have 110 degree F differential between fluid temperature versus room air temperature, when trying to maintain stability of inside temperatures when the OSA is at a 70 degree F differential. That works out to be 1.57 degrees F differential in emitter temperature per degree F difference between room air and OSA .



So, if 90 degrees F is the design cooling temperature, then it would require a water temperature of 20 X 1.57 = 31.4 degrees F. So, if we deduct 31.4 from the room temperature then it would indicate that the fluid going through the radiators would need to be (70 - 31.4) 38.6 degrees F.



Obviously, this fluid temperature is definitely below the dew point in many regions, but if a person were to send water through the system just slightly above the dew point, then it would reason that it is possible to significantly affect the internal MRT, which even on the cool side drives the bus of human comfort.



The dew point controls are available off shelf from numerous manufacturers, including Honeywell and Danfoss.



Air to water reversible heat pumps are also available off shelf. In areas like Baltimore, it will be necessary to have something to handle the latent loads, but the majority of the loads are sensible, and can be handled with radiators. Plus, you could use the heat pump to base load the heating demands of the heating system.



Just some food for thought...



ME

SWEI

radiator cooling

ME just described what I'm hoping to experiment with next summer at the hotel.  With our mild summer climate, and the immense thermal mass of this monolithic concrete post-and-beam building, we should be able to "put a hand on the flywheel" just enough to make it all work out.  Final cold water source TBD, but we're hoping we can get away with night sky cooling.

gennady

humidity

i think in these types of installations there still a need for conventional units handling latent heat and dehumidification, approximately 25% of the load, it will allow to raise water temperature over dew point.

Mark Eatherton

Absolutely...

one MUST handle the humidity in order to guarantee human comfort, but there is more than one way to skin a cat in that arena. Dessicant dryers, Energy Recovery Ventilators and obviously the DX type of dehumidifier. But if the majority of the load can be handled by "other" means, then the balance of the energy requirements required for humidity control are downsized considerably.



Radiant cooling is no longer an untried, unproven "concept", but rather it is more of a fine tuned science in delivering good human comfort. One of the largest airports in the world utilizes this means of cooling, and has had no issues with the dreaded condensate monster.



Avoiding loads in the FIRST place is going to give the biggest bang for the buck. It also results in a down sized physical plant required to deliver the goods.



ME

SWEI

avoiding loads

Was the name of the game for all the off-grid we did ~20 years back.  It still offers the best ROI -- and is still the hardest sell to a typical customer.

MikeG

My Experience

This is strictly from my experience in an old farmhouse with a newer modcon boiler with finned copper BB.  I had a window ac unit installed through the wall for two upstairs bedrooms.  Had to use a fan to move it around and also ceiling fans.  I installed a mini-isplit unit last year.  It only does the one room now but I may install another for the other room.  Very quiet, very efficient.  Some people do not like the looks of the indoor unit, but it sure beats the high price tag of a complete duct system in a retrofit like mine.  I do have a large 18.5K window unit in a downstairs window.  Yes it is pain to remove and install.  It keeps my downstairs comfortable temp amd humidity wise.  Again maybe not the most eye pleasing and this one is a bit loud and not as efficient as a mii-split.  I am considering a min-split for this area, probably with multiple indoor units.  I do use some ceiling fans to move the air.  House is well insulated and upgraded windows.  Retrofitting is always the issue in older homes.   

TonyS

Inverter ductless is

to air conditioning what modulating boilers are to heating. We have removed several attic units this year and replaced with multi unit minis. Several customers have called this week(high 90s) just to tell me how much they love them. If you are installing hydronic heat and not offering your customers ductless, you are missing a great opportunity for you and your customer.

gennady

Heat pump

Inverted compressor with ductless heat pump adding heating option as well for little extra $ in cost of equipment. labor is the same. Nice back up option.