All, today is the day I had committed to sending out the DRAFT request to equipment manufacturers of what is needed for full electrification. I apologize that I didn't have time or focus to get my thoughts together till now (I had intended to share this with Chris and others prior to sending to the full group, but just didn't get my thoughts down till now). At any rate, see below my first pass at what we would be requesting of manufacturers for the future electrification of the market place. Please review, comment, question, add, etc. This ended up being briefer than I initially thought it might be, but that may be good. Thanks all!
HVAC:
- Heat Pump Equipment tested and rated to 0°F OA and below:
- VRF – full heating mode
- Air to Water Heat Pumps
- Air to Air residential heat pumps (including PTAC replacements)
- Air to Water Heat Pumps capable of producing warmer water at 0°F:
- 100°
- 120°F
- 140°F
- Increased HP efficiency in heating mode at colder temperatures (focus on equipment operation for both cooling and heating across OA temperature ranges)
Domestic / Service Hot Water:
- Water-to-Water Domestic Heaters (ASME rated, capable of using CW loop to heat Domestic HW, Domestic/Potable equipment with double wall HX in place)
- Air to Water Heat Pump heaters with a focus on higher instantaneous capacity (requiring less HW storage)
For all equipment, provide US relevant certifications and testing. Including but not limited to:
- NFPA 70
- ASHRAE 15
- ASME
- UL 465
- AHRI
- Condensate defrost disposal is a primary concern with the current equipment stock
- Many existing PTACs are non-standard sizes, so doing retrofits is going to be challenging just on the issue of fitting into existing wall penetrations
- The shift to electric resistance heat all-too-frequently occurs at relatively high temperatures (40F), especially at recovery from setback. This overuse of electric resistance heat drives the effective annual COP down below 2, even if the "rated" COP is 3 or higher.
- At 0°F outdoor temperature, heat pump capacity appears to be 55% less than what it is at the 47°F test standard temperature - this could well lead to units being very oversized when operating at moderate temperatures. COPs also drop off at roughly the same rate (a 3.4 COP at 47F might be as low as 1.5 at 0°F)
- Only a couple of PTHP manufacturers (LG and GE) do reverse-cycle defrost.
- PTHPs are essentially unable to do energy recovery on integrated ventilation make-up air. The NYSERDA report goes so far as to say "It is recommended that high-efficiency cold-weather PTHPs do not have integrated make-up air."
Many of these issues are not as problematic for split-system air-source HPs, but there is still a significant market segment that is geared to PTHPs.