ASHP - Wet system

[ArgyllMC]

I see I have opened a huge debate. I am a bit sceptical about new fangled technology however I have seen heat pumps in action working well all through last winter at low costs so i am convinced this is the way forward.

I had decided on using a Diakin system, it uses R410A refrigerant, I appreciate the Sanyo system is perhaps the best however the cost is prohibitive and I understand it operates at an extremely high pressure; if it goes wrong I can see it going wrong in a big way?

Can somebody explain how to post a file attachment??

Thank to everbody for their views, I wish I had posted on here at the start of this long process!

Mark.

 

[D_Hailsham]

Can somebody explain how to post a file attachment??

The only attachment allowed by this site are pics. You can ether put them on an external site, e.g tinypic.com, or put them in you personal image folder. In either case you provide a link in your post.

Example

External Link [IMG]http://i9.tinypic.com/8dxytxf.jpg[/IMG] will display as

Internal Link [net]65839/70_49232730.jpg[/net] will display as

View media item 70
Click on the images button at top of page to create an album and download pics to your personal folder. When posting, click the "Show My Image" button below the typing box, find the image and click it. The link is automatically inserted in your post.

Large images will appear smaller in the post. Clicking them will enlarge them.

 

[kevplumb]

//www.diynot.com/forums/viewtopic.php?t=129539

could have saved yourself some typing dave

 

[D_Hailsham]

//www.diynot.com/forums/viewtopic.php?t=129539

could have saved yourself some typing dave

But you have to search for the info. There is nothing in the Help link or in the Upload Pictures Link. Forum info is not suitable as you have to search in the hope that there is something there. In any case it's mostly full of users' gripes about slowness, complaints about locked posts, moans about the mods, etc etc to be the most obvious place to look.

 

[kevplumb]

true

 

[ArgyllMC]

O.K. I think I have finally mastered the whole image thing.

View media item 26381
This is a very simple sketch. The 'sensible' option I refered to above involved putting a manifold in the space below the floor roughly where the door between the dinning room and hall is. Then feeding each of the emitters on 15mm pipe spurs.

I await comments..........

Thanks

 

[D_Hailsham]

Thanks for the diagram.

Are the emitter sizes the actual size you will need to buy or are they the heat loss from the room. If the actual size, would you please supply the heat loss for each room.

You say the mean water temp is 50C. Do you know what the design flow and return temperatures are?

 

[Agile]

My first comment is that you seem to have mostly put the rads on internal walls and not where possible under windows.

Tony

 

[ArgyllMC]

Thanks for the diagram.

Are the emitter sizes the actual size you will need to buy or are they the heat loss from the room. If the actual size, would you please supply the heat loss for each room.

You say the mean water temp is 50C. Do you know what the design flow and return temperatures are?

The emitters on the sketch are the size I will need to buy, i.e. they are the units required to give the correct (all are slightly larger) output for the room after applying the correction factor detailed above.

Room heat loss below

Hall 902W, Bedroom 1 1201W, Bedroom 2 621W, Bedroom 3 1208W, Bathroom 546W, Dinning Room 727W, Kitchen 596W, Toilet 592W.

My first comment is that you seem to have mostly put the rads on internal walls and not where possible under windows

I had read up and there were arguments for both putting them below windows and not. The arguement for not putting them below windows seemed to be more relevant to our house. We have long curtains so all heat rising from the radiators beneath windows would be getting pushed up behind the curtain and not emitting into the room as such.

Of course I stand to correct on all of the above.

Cheers guys for your quick responses.

 

[ArgyllMC]

Oh and the flow temperature.

The engineer has advised the flow will be 55 and a return of 45 therefore I assume the mean temperature would be 50.

Cheers

 

[D_Hailsham]

I've answered my first question by looking back at an earlier post where you say that the lounge needs 2267W, but the diagram shows a total of 4663W.

As for my second point about the mean water temp of 50C, I assume you are contemplating a low temperature system either split or monobloc. If you read the Technical Brochure page 6, you will see that LT systems work with a max temp of 40C and a differential of 5C. In this case the factor would not be 0.51, as given by the Myson catalogue, but 0.25. So radiators would need to be oversized by four times.

 

[Agile]

The advantages of ASHPs are receeding even further into the distance.

Thats even ignoring the question of actual operating costs.

ASHP works way better with UFH. Thats partly because the efficiency of the pump is higher when delivering lower temperatures.

Tony

 

[ArgyllMC]

Mmm I am going on what the engineer told me, now I HAD faith but that is changing.

The is going to be the LT split system, which looking at the booklet as you say does operate in a regime of temperature below how I had done the calculations. I will need to speak to the engineer this evening and see what his thought was, just as well I posted and didn't go on my merry way getting the emitters installed!

Thanks for highlighting this HUGE error.

 

[ArgyllMC]

Some confusion caused.

After a fairly frank discussion with the engineer who has contacted Diakin (i have sent him a copy of this literature as they seemed to think my interpretation was wrong) it would appear that they maintain a mean water temperature of 50 degrees is correct. The engineer has fitted several others and knows that the mean water temperature of 50 is achievable with the system and can be used for calculation purposes.

So it would appear my heater calculations are correct, whats the thoughts on the piping?

Nothing is ever simple!

 

[Biggles..]

If you realisticly think you can achieve 55degc from a hfc ashp specifically altherma without any electrical backup your in trouble.

Reality above 8deg c is about 45 hence why ufh is the preferred option as there's no need to blend the water temp down.

If it was cost that motivated you,then by the time you've oversized your rads,paid for the electric top up heating and had no heating in winter you'll reconsider how wise a choice altherma actually was when actually
Not having saved you that much in the initial payout.

I learnt how bad they were the hard way,hence why I'm throwing alot of my companies money to prove what actually is what.