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Discuss Does anyone use the heat loss/GSHP/ASHP spreadsheet provided by Gemserv? in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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deee

Hi all. My first post on here. I've been getting to grips with the spreadsheet provided via Gemserv from the online webinar. It seems like a really handy tool especially as the new MIS 3005 requires a room-by-room heat loss calculation. However the webinar and spreadsheet itself are not set up for a room by room. I've have tried altering this but my energy heat losses have become massive. Does anybody else use it?
 
Ive never seen it, for sizing heat pumps I use the tool on the Panasonic Pro club site
 
I use the Daikin spreadsheet tool (they have two - one whole house and one room by room).

That said I often do it old school using paper based room sheets (no computers when I started in HVAC!)
 
I have used and abused the Gemserv excel spreadsheet, added more rooms, and also added a radiator outputs tool, as I am often visiting older houses with radiators all plumbed in and we want to know whether they will work at lower flow temperatures.
Be careful though as I think there is an error in the annual kWh figure as it uses the external degree days figure on the internal heat losses as well! I will try to get hold of them and see what they have to say.
 
I have been sizing heating using Stelrad Stars for years, nobody has ever complained about being cold. It is free and all parameters can be adjusted to suit heat pump low flow temps.
 
Quinn do a free app too, I use a free tool sent to me made especially for hitachi and samsung
 
I have been sizing heating using Stelrad Stars for years, nobody has ever complained about being cold. It is free and all parameters can be adjusted to suit heat pump low flow temps.

I think you are missing the point. If Mr & Mrs Smith want a heat pump installed and hope to get a RHI income in the future then it needs to be MCS registered. Part of the registration process requires the use of the GEMSERV software which is a basic Excel spreadsheet. However, it currently produces an incorrect annual output as far as I can tell, because of the way it calculates annual heat losses on internal walls. I was wondering if anybody else had spotted the mistake and/or was using GEMSERV. I have looked at the Stars software and apparently it is compliant with BS EN12831 so could in theory be used as part of the quotation proces.
 
I guess I must be getting old and set in my ways. I hate learning new software. I have office 2010 in a box and am reluctant to load it, Office 2003 does all I want, but I bought for Excel 2007 and SAP calcs. I think the quinn one was based on one I tried year ago. Some of them were terrible buggy things to use, I tried several before sticking with stars, only problem is that Stelrad is not updating it now.
 
I guess I must be getting old and set in my ways. I hate learning new software. I have office 2010 in a box and am reluctant to load it, Office 2003 does all I want, but I bought for Excel 2007 and SAP calcs. I think the quinn one was based on one I tried year ago. Some of them were terrible buggy things to use, I tried several before sticking with stars, only problem is that Stelrad is not updating it now.

Stelrad seem to be going down the "app" route, although the latest version of Stars seems to be updated this year. I am in the process of signing up to the on-line version to see if it is any good. The MCS GEMSERV is not great, although being simple I can fiddle about with it and amend to suit my needs.

There seems to be a demand for eegits like me to do the number crunching for local plumbing companies, so we will see what the future holds.
Are you MCS registered?
 
I have still have the CD version of Stars. I just realised it is 2002 Issue 3.1, how time flies, so I have hundreds of historic calculations saved. I will try to update it with Stelrad now, the auto update link is broken on the 2002 version, that's why I thought it hadn't been updated.

I am now starting to quote heat pumps for new builds on heat loss per square metre to save time, as it seems I have to quote 10 projects to get one!! 40-50W /m2 for new builds and around 70W for new refurbs and 100w /m2 for older properties with caviity walls and double gazing. I would hope not to use 150W/m2 even for solid walls and single glazed older houses, but I would be more careful with these and do a more stringent heat loss using STARs. I think the simplified SAP asessment operates in a similar fashion to the 'whole house boiler sizing', where you plug in the area of outside walls, age of property and location etc, but I am sure you will tell me there is more to it than that.

The amount of air changes are the killer for getting your accuracy in heat loss calculations, new houses have much less air change than the defaults in Stars, new builds now kitchens are 2, bedrooms 1 and lounge dining is 1.5/hour. Open flues in lounge can add another air change/hour. Stars alos tends to oversize bathroom radiators, it assumes a default 3 air changes and 22 degrees air temp, but not many bathrooms have 3 air changes / hour all day and are heated constantly to 22 degrees.

You never really know what the air change rate is on an older property. I have had very leaky old houses and some seemingly very air tight, old suspended ground floors can be particularly bad, especially if floor joists have rotted and the floor has dropped. It is safe to say that an old cottage with exposed beams and single glaze windows are usually well ventilated as well!! Heat pumps not my favouritre product for an old house, it is safer to use a pellet boiler with radiators, at least is has some punch and the cost/kW capacity is much lower than a heat pump.

Yes, I am MCS registered, I was assessed on the new version of MIS3005 for heat pumps last November, I didn't realise that I wasn't in force at the time. I did the main 4 MCS technologies, solar pv, solar thermal, biomass and heat pumps (ground and air).

I have always done my own heat loss calcs on stars or other software.
 
"The amount of air changes are the killer for getting your accuracy in heat loss calculations, new houses have much less air change than the defaults in Stars, new builds now kitchens are 2, bedrooms 1 and lounge dining is 1.5/hour. Open flues in lounge can add another air change/hour. Stars alos tends to oversize bathroom radiators, it assumes a default 3 air changes and 22 degrees air temp, but not many bathrooms have 3 air changes / hour all day and are heated constantly to 22 degrees."

I know what you mean, I had a bloke who wanted a heat pump for an aircraft hanger (honest), the ventilation made a huge difference to the final result. I guessed that it took 5 to 10 minutes with the doors open to get an aircraft out, therefore you would want "big heat" and not underfloor heating with GSHP as it would take all day to recover.

Full SAP for new houses, can get quite geeky and involved and it has been shown to be in the right ball park of measurements of new houses, if the inputs are correct (garbage in- garbage out). Passivhaus is even more involved and geeky.

I presume you use stars for your MCS quotes?

Thanks for mentioning the stars thingy, I would not have found it otherwise.

regards

Alex in Norfolk
 
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