Combining electric cove heaters with PV
In a recent blog, Designing an HVAC System for a Cold Climate, Malcolm Taylor is quoted as recommending electric cove heaters, and a link to the Comfort Cove line from Radiants Systems, Inc. is provided in the blog text. Searching Green Building Advisor turns up half a dozen other references to cove heaters, all very short, and all positive. I wonder if there is more useful advice on choosing and using this technology for supplemental heat.
In my case, we have grid-tied PV at the regulatory maximum of 10 kW, and we have another 2 kW of PV panels currently sitting idle. We would like to displace some of the propane burned to heat our inefficient early 70s adobe and frame house (originally built for Bob Dylan). Our solar contractor has proposed connecting the idle PV panels to baseboard convectors. I’m leaning toward cove heaters, both because I prefer to have a radiant component to the supplemental heat, and because furniture blocks the majority of the wall perimeter.
The solar guy is talking about running the direct current output of the PV panels to the resistance heaters, avoiding an inverter, and increasing efficiency (he says). I’m not sure if the heater manufacturers will approve the use of DC current, and I’m interested in GBA opinions. Later, we hope to connect these PV panels to an electric water heater, as we continue to try and improve the efficiency of this problematic house (don’t buy a house designed by a poet’s manager). Perhaps a mini-split is in our future, after air sealing and insulation are complete, but does any of this make sense as an interim approach?
The house is near Santa Fe, NM, a bit over 6,000′ in elevation, climate zone 5. The Heating Degree Days (base 65) listed on various sites range from 4,500 to a bit over 6,000, with roughly 5,600 being the mode.
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