Are there any small water-source heat pumps using scroll compressors
I am trying to find a Water-Source Heat Pump (WSHP) to be used as a supplemental cooling unit for a radiant heating/cooling system.
I’m having no trouble finding the right size WSHPs for this job (sub 2-ton), but all of the small units use rotary compressors. Left idle, rotary compressor are prone to rusting and premature failure. This will be a vacation home, so that scenario is likely.
Has anyone come across a sub-2 ton WSHP with using scroll compressors? Thank you in advance.
Replies
Rusting? You know the compressor and motor inside the hermetic shell is sitting in oil right? I've been an HVAC contractor for 33 years and I have never found a "rusted compressor failure" regardless of compressor type. Your getting bad info.
Thanks for the info. Would you say then that rotary compressors sitting idle for too long isn't a concern? Have you dealt with many rotary compressors in you HVAC work? If so, what has you experience been with their logevity vs. scroll compressors? Appreciate any additional information you might have.
Rotary compressors are not that common, you may be thinking of a reciprocating compressor which used to be the typical type before scroll compressors. Compressors fail for many reasons but sitting idle is not a concern. You are planning to put well water through the WSHP or is it a closed loop design? Trying to understand your "radiant cooling" comment...I get radiant heating obviously and I understand the concept of radiant cooling, but putting it in actual operation is another matter...that sounds tricky without a serious controls/DH plan. Never seen it residentially (or commercial for that matter although it exists where conditions allow I hear). Was the radiant cooling comment a typo or you trying that?
Thanks for the reply. I am trying for a radiant heating and cooling system. System will be closed loop running distilled water and embedded in concrete floors. The in-floor system will provide nearly all the BTU needs for heating, but I will need a supplemental cooling system in the summer. This is where the small WSHP comes in. I will probably need 6,000-12,000 BTU supplement in-floor cooling. The WSHP will use the same supply water as the floors, and should be the only condensing area in the entire system.
To clarify, all of the manufactures I look at (trane, water furnace, aaon, daikin, and carrier) use rotary compressors on any WSHP's less than 2 tons (Carrier does manufacture a 1.5T WSHP using scroll compressors). To your point, scroll compressors are the norm for the HVAC industry. My guess is they took over because they fail less than their predecessors (only 2 moving parts). What I'm trying to find is any manufacture out there that uses smaller scroll compressors. I know they exist... Copeland makes a 1-ton model, but I haven't found the WSHP it fits on.
The controls to implement radiant cooling shouldn't be that difficult. To start, in most regions of America any home being built today should have whole-house dehumidification. Houses are just too tight today (thankfully) and there's too many materials that don't like moisture in home construction. So if that's true, all you have to do is make sure your supply water temp never drops below dew point temp and radiant cooling works. Even when it's 100+ degrees out, ERVs will be pulling in a bulk of the air, and cooling that air. That should allow me to keep cooling temps relatively low. There will be thermostats and humidistats monitoring real-time though. Whatever heat I can't dump into my floors will be dumped into the WSHP.
Hope this help. Appreciate the info.
I have a vacation home, and I have the wifi connected system run the dehumidifier and whole house fan for a couple hours each day. It's good for the structure. I'd go with the standard equipment and make sure the system doesn't in fact sit idle. Best of both worlds.
http://elamarrado.com/2016/04/22/rotary-vs.-scroll-pros-and-cons-of-two-common-ac-compressor-types/