Grant Aerona r290

[JohnMo]

2 minutes ago, marshian said:

 

Now you've gone and done it

Do I care - no😇

[JamesPa]

2 hours ago, JohnMo said:

The thermal Mass, or the heat capacitance

Should be heat capacity according to my degree in physics.

 

Personally I don't have an objection to thermal mass as a colloquial term.  Mass, after all, is responsible for inertia, and the heat capacity results in thermal inertia. 

 

One can be too precious over these things although, like steamy tea, I get fed up of unit abuse mostly because it tends to indicate that people don't understand the underlying concept.

[LeeVanCleef]

Thanks for the input all. To cover JohnMo’s queries

 

1. Do you have open fire places?

- 2, but boarded up. hard to say how well blocked up - see 4
 

2. Are rooms drafty, can you feel a breeze around closed doors, both internal and external.

- Nothing obvious at present 

 

3. What sort of build is the house.

- timber frame with block outer. 90s build. 280m². Insulated timber suspended floor. Insulated loft.

 

4. @JamesPa favourite, what was or is your current operating regime for your heating system?

- We have only been in the house since March so haven’t had a winter yet. Agreed that 6 months of measurements through the winter months would likely tell us a whole lot

 

I worked through the heat loss calc shared here previously and that was suggesting about 9kW of losses. Some more sensitivities to run on that I think.

 

I’ve also been investigating the provenance of the Grant machine. I’m not sure if the OEM of these newer R290 units has been confirmed yet?

 

 

 

[sharpener]

6 minutes ago, LeeVanCleef said:

I’ve also been investigating the provenance of the Grant machine. I’m not sure if the OEM of these newer R290 units has been confirmed yet?

 

In 2003 it was said to be Chofu (see upthread). Maybe the delay in getting to market was bc of a change of horses.

[JohnMo]

28 minutes ago, LeeVanCleef said:

90s build. 280m²

So take that in the round, we are 192m² and have a heat loss of 3kW, you are about 50% bigger, so that puts you to 4.5kW. We also have MVHR, triple glazing and very good insulation, so you aren't going to far away from 9kW. I would concentrate your effort finding out depth of modulation, that is possibly the more important aspect. 

[JamesPa]

1 hour ago, LeeVanCleef said:

worked through the heat loss calc shared here previously and that was suggesting about 9kW of losses. Some more sensitivities to run on that I think.

Well you don't want the 15kW grant then unless it's sticker output is a joke.

 

If you can refine the figure by any means it might help choose between one if the many 8kW ish machines and one of the 10-12 kW machines.  I had the same dilemma but managed to convince myself that my loss was no more than 8kW and probably only 7 so ended up with the 7kW sticker output (8.5 actual according to the spec) Vaillant.  Yours sounds like it may swing the other way

Edited September 5 by JamesPa

[sharpener]

 

2 hours ago, LeeVanCleef said:

3. What sort of build is the house.

- timber frame with block outer. 90s build. 280m². Insulated timber suspended floor. Insulated loft.

 

HG cheat sheet suggests 30 - 50 W/m^2 so 11.2 to 14 kW, Vaillant 12kW sounds a good match. The 10kW is basically the same unit so has the same minimum output.

 

2 hours ago, sharpener said:

 

In 2003 it was said to be Chofu (see upthread). Maybe the delay in getting to market was bc of a change of horses.

 

2023 of course.

 

[JamesPa]

18 hours ago, sharpener said:

 

HG cheat sheet suggests 30 - 50 W/m^2 so 11.2 to 14 kW, Vaillant 12kW sounds a good match. The 10kW is basically the same unit so has the same minimum output.

Or the 11.2 Mitsubishi.  Roughly same min output from what I recall.

[sharpener]

5 hours ago, JamesPa said:

Or the 11.2 Mitsubishi.  Roughly same min output from what I recall.

 

12kW Vaillant is v conservatively rated so good for a lot more, don't know about the Mitsi but @JohnMo can probably tell us.

[sharpener]

5 hours ago, JamesPa said:

Or the 11.2 Mitsubishi.  Roughly same min output from what I recall.

 

12kW Vaillant is v conservatively rated so good for a lot more:

 

 

Don't know about the Mitsi but @JohnMo can probably tell us.

 

 

Edited September 6 by sharpener
Performance graphs added

[JohnMo]

5 minutes ago, sharpener said:

Don't know about the Mitsi but @JohnMo can probably tell us.

Could of told you a couple of weeks ago, but deleted loads of stuff off the phone, and the Mitsubishi tech manual was one of them.

[JamesPa]

27 minutes ago, sharpener said:

Don't know about the Mitsi but @JohnMo can probably tell us.

 

Mitsi firmware clamp output so its 11.2kW more or less irrespective of FT and OAT.  Well thats true at least for the databooks from Mitsi (which BTW are very good) that I have looked at.

Edited September 6 by JamesPa