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Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

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Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#461

Post by [deleted] »

criddell wrote: post #429
brudgers wrote: post #254

Earlier quoted context omitted.

You don't want an over-sized system. They short cycle. An over-sized system can quickly cool to the thermostat setting, but leave the latent heat in the water vapor in the air. So you experience the "feels like" temperature...it's not the heat, as they say. A properly sized system runs long enough to condense water vapor and with it remove the latent heat from the air.

The short cycle argument only really applies to older and low end systems that are not variable speed. A variable speed system integrated with a humidifier should be able to slowly bring the temperature down, making sure that the cooling does not get ahead of the dehumidifying. I want an “oversized” system that can do > 20F temperature drops. I know they exist because a lot of commercial spaces have them.

[deleted]

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#462

Post by cmui »

papertokyo wrote: post #365

Small suggestion for your preorder buttons: the gray/white combo doesn't have great contrast and might be perceived as being in a disabled state. I'd recommend black/white on light backgrounds and white/black on dark backgrounds to make them fit with the (very nice) industrial design theme. Our building (Western Canada) has a heat pump system and it's very capable of keeping the apartment comfortable in all seasons a…

Thanks for the suggestions!

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#463

Post by cmui »

adanto6840 wrote: post #377
cmui wrote: post #267

Earlier quoted context omitted.

I'm sure there's some contractor unit that lets you see the live readout of compressor speed. As for Electric Air - we want to give visibility into system operation, what's the input electrical power, what's the output thermal power, how much have you spent on heating so far, and what's your average COP for a given time period (ratio of heating out/electrical in).

If you remove the service panel there's a screen that displays what capacity they're running at. My installer had some issues initially, and Bosch actually had 2 regional reps (corporate) visit the site themselves. I'm sure the protocol exists somewhere, but the guys they sent wouldn't have known and I don't believe they connected anything to the board -- the Bosch reps couldn't even correctly explain to me how/what…

Wow, sorry you had to go through that setup hassle. I would also say you are probably in the 1% of motivated homeowners trying to get those details right. A lot of this difficulty seems like it stemmed from trying to get the Ecobee to play nice with the Bosch. With Electric Air I hope to avoid setup issues like this, the thermostat is specifically designed to work well with the other equipment.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#464

Post by tguvot »

criddell wrote: post #192
buttersbrian wrote: post #172

Earlier quoted context omitted.

Have you considered assessing your home's insulation?

We did. We had more insulation blown into our attic (it gets crazy hot up there) and we are now looking for new windows.

actually i'll advise you to take a look at temperature of your walls. both inside and outside. they have a bunch of thermal mass. during the summer they effectively heat the air inside the house. unless you manage to cool walls somewhat (lets say during night), hvac will have to really fight to keep temperature down. I live in bay area and I installed whole house fan which is typically runs through the night at summer. For most of the cooling season it sufficiently cools air and walls in order to require only a couple hours of hvac a day.

additional point, you wrote that you have current system installed 15 years ago. back than design temperatures (i.e. how hvac sized based on outdoor temperature) were different. recent updates sometime bring those temperatures up by 10F or so, what can result in extra half a ton - ton of hvac.

you could retain company to make a proper hvac sizing (called manual j calculation). hvac contracts from my expirience won't do it.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#465

Post by aloukissas »

cmui wrote: post #443
aloukissas wrote: post #415

This is great to see. I have a question around the "a delightfully uniform temperature in each room". I live in a 3-story townhome, which has largely non-uniform temperature across floors (since warm air travels up). So, cold lower floors in the winter and hot upper floors in the summer. AFAICT, this is pretty common with central duct systems and the usual fix is to switch to split-unit systems. How does your product…

Good question. The uniform temp is really within a room, what you're describing is the not uncommon experience of having unbalanced duct work. A few options for you (1) DIY or pro duct balancing. You change the position of dampers and vents, might have to modify duct work (2) actuated zone dampers, these live in the duct work and install is expensive (3) a smart vent that you can DIY, battery life is surprisingly goo…

Thanks for the pointers! Coming from Europe, I really love ductless split systems, so that's probably my preference.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#466

Post by lazyasciiart »

cmui wrote: post #381
samstave wrote: post #340

Earlier quoted context omitted.

Crazy idea: Pressure plates in the streets which are pressed when cars drive over them - pushing fluids through your coils, but connected to multiple units on either side. Harvest the kinetic energy of cars passing through the streets to apply pressure to pumps that feed fluids through the system, capturing that energy in a dynamo way? Put these plates in every high trafficked area. Piping the pumping action from par…

I like the out of the box thinking! Unfortunately I think this one doesn't quite pass first principles. Any pumping action from the vehicles would be extra work they have to perform, so you just shuffle the energy expenditure from your local heat pumps, to a fleet of vehicles.

Aren’t the cars already performing that work, just letting the energy dissipate into the road surface instead of going somewhere?

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#467

Post by time4tea »

Seems expensive. I just got a ~13kW / ~45kbtu Mitsubishi Ecodan air/water plus new hot water tank etc for £10k (plus £5k government grant)

No details on refrigerant and therefore GWP / F-gas that I could find.

On the plus side (for you!), mitsubishi data/api/app sucks so bad, I can only imagine it is powered by EJB - there is so much potential upside there.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#468

Post by liminalsunset »

daredoes wrote: post #271
cmui wrote: post #88

Earlier quoted context omitted.

It's something we'd definitely consider. Is the desire to have thermostat control via any third party? edit - The current plan has been Matter/thread Homekit + Google Home integration. We can expose at least temperature control via this to everyone.

The desire is to have any control/knowledge you'd want to have as the creator/developer. I want to be my own mechanic, and if I'm not that mechanic I want to be able to have anyone be that mechanic. Do you want to know what the active airflow rate is? I want to know what the active airflow rate is. Do you want to know power consumption? I want to know power consumption. Do you have a way to write unique schedules/pro…

Speaking of heat pumps and granular control, I recently figured out that some Midea heat pumps (usually sold rebranded to various brands) contain two interfaces to get and set detailed information:

1) Detailed diagnostics i.e. RPMs, feeds, speeds, currents, temps etc can be read from the high voltage signal line between the indoor and outdoor unit - there is an official tool (search "Dr. Smart Midea" on YouTube) that does this. If you look in the right places, there is a PowerPoint with a schematic of the PHY that you need to interface with this using a LV isolated controller

2) The outdoor unit can be driven manually using the same tool using an i2c port that is on the PCB on the outdoor unit

I have the new generation of their Dr. Smart tool, which I haven't had the time to thoroughly test or document. If there is interest I will likely try to reverse engineer and document these protocols properly.

> "I want to be my own mechanic, and if I'm not that mechanic I want to be able to have anyone be that mechanic."

> "Do you want to know what the active airflow rate is? I want to know what the active airflow rate is. Do you want to know power consumption? I want to know power consumption. Do you have a way to write unique schedules/programs that get executed on the heat pump? I want a way to write unique schedules/programs that get executed on the heat pump."

There's one feature of this diagnostic interface that I really really like. It allows you to "drive" the hardware of the unit manually, like Program Auto mode on a camera. You can manually set the frequency of the compressor and fan, and the control board will continue to enforce safeties.

I haven't tried yet, but something I really want to try to implement myself is "frequency lockout". This is a common feature on commercial variable frequency drives. I noticed that under some operating conditions, the unit vibrations resonate with the building and create unpleasant sounds - I'd like to program it to never dwell on that frequency and skip over it.

> The desire is to have any control/knowledge you'd want to have as the creator/developer.

While I was exploring this, I had this in mind constantly. I definitely had this diag interface in mind when I was selecting a unit.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#469

Post by schiffern »

Based on the location of the filter, it looks like the air return is supposed to come in... from the bottom?

In most home unit I've seen, the return air duct connects on the side. Do you plan to offer anything in that configuration? Thanks!

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