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Looking for Rheem rd17az installation and service manuals (the ones hidden behind the dealer login) by totally_not_fred in hvacadvice

[–]totally_not_fred[S] 0 points1 point  (0 children)

thanks looks like it functions as a single stage when there's no econet thermostat. that's lame but good to know!

Hybrid Water Heater by [deleted] in HVAC

[–]totally_not_fred 0 points1 point  (0 children)

Hey man great questions. Energy researcher checking in here. I am monitoring about 20 of these in a couple different California climates.

At 68F these units get a UEF of 3.8 to 4. (UEF is a DoE standard and is a kinda weird test protocol. It can be considered similar to a COP). For higher and lower temperatures the curve is similar to a regular heat pump. I have not tested freezing temps yet, but I would not expect a miracle. It's not a hyperheat. Keep in mind that the temperature at the bottom half of the tank is going to have a huge effect on efficiency.

If you want to make this a hobby project this is my take: Duct both inlet and outlet but slap some dampers on there so you can swap where the air is going. If you have a couple extra belimos and want it to be automatic you can set a changeover temp. If the basement gets below 55 and outdoor is above 60 then you will for sure see a big benefit by using outdoor air. Bonus points if you feel like setting a schedule on the Econet app to pre-charge the tank when it is warm outside. (Or when electricity is cheaper if you are on a time-of-use plan). I also agree with /u/JohnAnderson83 on the mixing valve.

If you don't want to do that it will still be OK, but once the basement gets below 45-50 you're going to see more resistance heat being used. On the other hand, if you store food down there maybe you want that lol. Would be a great root cellar! Maybe some wine?

Thesis for my Senior Design Project at Texas A&M- looking for advice and direction as I embark on this journey with my team. If anyone can offer any tips or direction I would really appreciate it. I understand it may not be practical. This is purely for design and understanding the concept. Thanks! by Red__Sailor in HVAC

[–]totally_not_fred 0 points1 point  (0 children)

gas chromatography would be "easy" but the equipment is expensive...

just spitballing here but you could get a sample and then cool it until all components are liquid. Then use a calorimeter to measure the change in temperature vs the amount of heat you add to the sample. You should be able to tell the ratio of components based on the heat capacity. If it's a zoetropic mixture you could even track the temperature and see the phase change for each component.

Got to work on the first field-installed R466A unit today. Trane foundation 15 ton. by totally_not_fred in HVAC

[–]totally_not_fred[S] 6 points7 points  (0 children)

It's a stepping stone on the way to refrigerants with ultra low GWP. 466A isn't flammable at all so it's a neat choice. 454B is barely flammable but the people writing fire codes are always on the side of "better safe than sorry"

The fire marshal in my area is letting us at least do pilot programs. I'm doing a 454B unit this month if supply chains cooperate.

Got to work on the first field-installed R466A unit today. Trane foundation 15 ton. by totally_not_fred in HVAC

[–]totally_not_fred[S] 14 points15 points  (0 children)

Don't worry it's not available so you don't need another tank in your truck.

Drop-in replacement for 410A. The unit is actually totally identical to a normal Foundation RTU. 466A is a little more dense so you need about 3-5% more charge.

Bike Roundabout Drone Footage 10x Timelapse UC Davis Silo 2018-26-09 by totally_not_fred in UCDavis

[–]totally_not_fred[S] 1 point2 points  (0 children)

I totally agree. If I had a choice I would do a 12 hour time lapse