GSHP poorly sick
Discussion
caziques said:
Just some observations.
A heat pump will produce water at a maximum of 40c,
When working you should have maximum of 35c going into the floor, 25-30c coming out.
Couple of points.A heat pump will produce water at a maximum of 40c,
When working you should have maximum of 35c going into the floor, 25-30c coming out.
Heat pumps should be able to produce hot water at 65 Deg C, or there should be a back-up immersion heater to heat the stored hot water up to 65 Deg C. (to inhibit legionela etc)
Any heat pump I've worked on will heat the underfloor or radiator circuit higher than 35, most will achieve 55 easily enough.
Cogcog, let us know how you get on at your meeting.
JM said:
caziques said:
Just some observations.
A heat pump will produce water at a maximum of 40c,
When working you should have maximum of 35c going into the floor, 25-30c coming out.
Couple of points.A heat pump will produce water at a maximum of 40c,
When working you should have maximum of 35c going into the floor, 25-30c coming out.
Heat pumps should be able to produce hot water at 65 Deg C, or there should be a back-up immersion heater to heat the stored hot water up to 65 Deg C. (to inhibit legionela etc)
Any heat pump I've worked on will heat the underfloor or radiator circuit higher than 35, most will achieve 55 easily enough.
Cogcog, let us know how you get on at your meeting.
Unlike all other forms of heating the efficiency of a heat pump varies depending on various conditions. Hence heating water from 25-35 with a heat pump uses less energy than heating it from 45-55. Anyone who designs an underfloor system with a heat pump that heats water higher than 35c doesn't know what they are doing.
It's nothing to do with the capabilities of a heat pump, it's all to do with understanding the physics. A good ground source design could run at 6:1 efficiency for underfloor heating, a bad one at 3:1.
It's unfortunate that cogcog (and neighbours) now have a jaundiced view about heat pumps when they can be the most cost effective way of providing heat. By the sounds of it the problems are all to do with the installers.
100kW hrs a day!
Someone has some serious explaining to do.
Take 20kW hrs a day off for normal household stuff - leaves 80.
Heat pump should be at least 3:1, and in reality should be nearer 5:1. Anything from 240kWhrs of energy (ie 10 every hour of the day) or 400kWhrs a day of energy going into a new build house! You could this with fan heaters everywhere.
Things are a bit different in NZ as the day temperatures tend to be warmer (less heat loss), but I use air source (in theory less efficient) and invariably houses here have aluminium window frames (like having small radiators stuck in your walls) and are single story (much bigger surface area to volume leading to heat loss), but even so our heavy users consume half this amount under extreme conditions ie 40kW hrs a day for heating.
Someone mentioned about insulation, assuming all the pipes are inside the house leaving them without insulation means they act like a small radiator - as the idea is to get heat into the house it's generally a waste of time to insulate.
Someone has some serious explaining to do.
Take 20kW hrs a day off for normal household stuff - leaves 80.
Heat pump should be at least 3:1, and in reality should be nearer 5:1. Anything from 240kWhrs of energy (ie 10 every hour of the day) or 400kWhrs a day of energy going into a new build house! You could this with fan heaters everywhere.
Things are a bit different in NZ as the day temperatures tend to be warmer (less heat loss), but I use air source (in theory less efficient) and invariably houses here have aluminium window frames (like having small radiators stuck in your walls) and are single story (much bigger surface area to volume leading to heat loss), but even so our heavy users consume half this amount under extreme conditions ie 40kW hrs a day for heating.
Someone mentioned about insulation, assuming all the pipes are inside the house leaving them without insulation means they act like a small radiator - as the idea is to get heat into the house it's generally a waste of time to insulate.
caziques said:
100kW hrs a day!
Someone has some serious explaining to do.
Take 20kW hrs a day off for normal household stuff - leaves 80.
Heat pump should be at least 3:1, and in reality should be nearer 5:1. Anything from 240kWhrs of energy (ie 10 every hour of the day) or 400kWhrs a day of energy going into a new build house! You could this with fan heaters everywhere.
Things are a bit different in NZ as the day temperatures tend to be warmer (less heat loss), but I use air source (in theory less efficient) and invariably houses here have aluminium window frames (like having small radiators stuck in your walls) and are single story (much bigger surface area to volume leading to heat loss), but even so our heavy users consume half this amount under extreme conditions ie 40kW hrs a day for heating.
Someone mentioned about insulation, assuming all the pipes are inside the house leaving them without insulation means they act like a small radiator - as the idea is to get heat into the house it's generally a waste of time to insulate.
Something is very wrong. Although we are 4 adults we have had the GSHP set at 19 degrees, which isn't 'hot'.Someone has some serious explaining to do.
Take 20kW hrs a day off for normal household stuff - leaves 80.
Heat pump should be at least 3:1, and in reality should be nearer 5:1. Anything from 240kWhrs of energy (ie 10 every hour of the day) or 400kWhrs a day of energy going into a new build house! You could this with fan heaters everywhere.
Things are a bit different in NZ as the day temperatures tend to be warmer (less heat loss), but I use air source (in theory less efficient) and invariably houses here have aluminium window frames (like having small radiators stuck in your walls) and are single story (much bigger surface area to volume leading to heat loss), but even so our heavy users consume half this amount under extreme conditions ie 40kW hrs a day for heating.
Someone mentioned about insulation, assuming all the pipes are inside the house leaving them without insulation means they act like a small radiator - as the idea is to get heat into the house it's generally a waste of time to insulate.
The boiler ratio should be 3.5
I noticed that the boiler 'shower/hot water' light was often on when we were not taking water and put it down to the system filling the loop (as the house is quite large (3200 sq feet and almost 50 yards long so at certain times of day the system keeps hot water in the pipes so you don't have to wait for hot water to travel the 50 yards) but the loop is set on timer only for 7am-9am and 5pm-7pm.
And the washing machine has been plumbed into the hot supply rather than the cold! How basic a mistake is that? Shrunk my wife's best top. Not a happy girl.
I had estimated use of about 17000 KWHs a year based on the area and the fact we have a very good insulation rating.
Engineers here in the morning so will update then.
Report back when someone's been to have a look.
If the heat pump is doing hot water as well that alters things to some extent - and would explain copper pipe everywhere.
I just ponder how it has been designed. There is a fundamental problem trying to do underfloor heating and hot water with one unit. Hot water needs to be at say 50-60, underfloor at 35.
One golden rule - the water for underfloor must NOT be taken to high temperatures at any point - it ruins the efficiency.
If the heat pump is doing hot water as well that alters things to some extent - and would explain copper pipe everywhere.
I just ponder how it has been designed. There is a fundamental problem trying to do underfloor heating and hot water with one unit. Hot water needs to be at say 50-60, underfloor at 35.
One golden rule - the water for underfloor must NOT be taken to high temperatures at any point - it ruins the efficiency.
Cogcog said:
System back up and running. Nobody is sure why it lost pressure and stopped but they pressure tested all 3 arrays twice and the manifolds; no problem although the pressure test at 3 bars did flush through some sand and lots of air.
Fingers crossed.
If they were getting air and sand out it sounds like it wasn't vented and flushed properly in the first place.Fingers crossed.
Fingers crossed it's all ok now though.
caziques said:
There is a fundamental problem trying to do underfloor heating and hot water with one unit. Hot water needs to be at say 50-60, underfloor at 35.
Only if the unit/system hasn't been designed to do it.There is no fundamental problem with a heat pump heating water to 65 degrees C as I said before.
Virtually all the ones I've worked on have been dual temperature.
Not really relevant to this problem, but my mum had a GSHP installed recently for heating/hot water. The installers buggered it up three times before finally getting around to doing it properly via another engineer so my mum would sign it off.
The person who raised the issues about it not being installed right before being signed off, my brother, who did 80% of his installation himself.
It's rather worrying but as others have said, not many people are good with these, and even those who are meant to be are not.
I'd try find someone very good with them to help in assuring it's fixed properly before too much time passes and the builders decide they don't want anything to do with it any more... not sure how long the warranty is!
Best of luck with it
Dave
The person who raised the issues about it not being installed right before being signed off, my brother, who did 80% of his installation himself.
It's rather worrying but as others have said, not many people are good with these, and even those who are meant to be are not.
I'd try find someone very good with them to help in assuring it's fixed properly before too much time passes and the builders decide they don't want anything to do with it any more... not sure how long the warranty is!
Best of luck with it
Dave
JM said:
caziques said:
There is a fundamental problem trying to do underfloor heating and hot water with one unit. Hot water needs to be at say 50-60, underfloor at 35.
Only if the unit/system hasn't been designed to do it.There is no fundamental problem with a heat pump heating water to 65 degrees C as I said before.
Virtually all the ones I've worked on have been dual temperature.
RedLeicester said:
JM said:
caziques said:
There is a fundamental problem trying to do underfloor heating and hot water with one unit. Hot water needs to be at say 50-60, underfloor at 35.
Only if the unit/system hasn't been designed to do it.There is no fundamental problem with a heat pump heating water to 65 degrees C as I said before.
Virtually all the ones I've worked on have been dual temperature.
I was working on an air source unit last year that was used for only radiators in a house. It was reaching 50's as well. Hot water was an immersion heater on that one.
I work with a couple of others that are light commercial, just for space heating (one is another swimming pool)
But other than that, I think, all the domestic air or ground source units I've dealt with have been dual temperature, some with a mix of underfloor and rads on the heating side.
JM said:
I have a domestic customer who uses a GSHP to heat his swimming pool, it's single purpose and easily achieves mid 50's.
I was working on an air source unit last year that was used for only radiators in a house. It was reaching 50's as well. Hot water was an immersion heater on that one.
I work with a couple of others that are light commercial, just for space heating (one is another swimming pool)
But other than that, I think, all the domestic air or ground source units I've dealt with have been dual temperature, some with a mix of underfloor and rads on the heating side.
Yep with you on all that, hence my surprise that Caz only has single-use boxes.I was working on an air source unit last year that was used for only radiators in a house. It was reaching 50's as well. Hot water was an immersion heater on that one.
I work with a couple of others that are light commercial, just for space heating (one is another swimming pool)
But other than that, I think, all the domestic air or ground source units I've dealt with have been dual temperature, some with a mix of underfloor and rads on the heating side.
We are going through the MCS acreditation at the moment for an industrial heat recovery product I have designed.
I have had to do a couple of courses and what has suprised me is the lack of refrigeration knowledge, most of the guys taking the courses come from a plumbing background, to understand the implications of designing an efficient system you really have to have a grasp of the refrigeration cycle.
I have had to do a couple of courses and what has suprised me is the lack of refrigeration knowledge, most of the guys taking the courses come from a plumbing background, to understand the implications of designing an efficient system you really have to have a grasp of the refrigeration cycle.
gareth h said:
We are going through the MCS acreditation at the moment for an industrial heat recovery product I have designed.
I have had to do a couple of courses and what has suprised me is the lack of refrigeration knowledge, most of the guys taking the courses come from a plumbing background, to understand the implications of designing an efficient system you really have to have a grasp of the refrigeration cycle.
When we were looking in to GSHP and ASHP I was appalled at the number of companies who knew less about what they were selling that I did, and all I'd done is spent a day reading on Google... The discrepancys and disagreements over depth / spread / size of ground arrays, COP issues with differening types of pumps, the impact / effects of start up amperages, the list went on.I have had to do a couple of courses and what has suprised me is the lack of refrigeration knowledge, most of the guys taking the courses come from a plumbing background, to understand the implications of designing an efficient system you really have to have a grasp of the refrigeration cycle.
In the end I finished up with a company who actually made their own systems from scratch rather than just imported someone else's box - everytime I had a question, the answer was "hang on, I'll get an engineer" or "I'll ask the designer if we can make it do that". Way more reassuring than a salesgibbon who just wants you to sign on the dotted line for something which is blatantly not fit for purpose, but is happy to take tens of thousands of pounds off you for the privilege.
As Red Leicester has found in the UK - many heat pump people who claim to be experts are useless - they simply don't know what they're talking about.
Basic fundamental of a heat pump - the closer the temperatures you are pumping from/to, the higher the efficiency. For example, 10c outside, heating water from 25 up to 30c for underfloor and the system could be 5 or 6:1 efficient.
-5 outside - and you are using a heatpump to take water from 50-60c for radiators. Perhaps 2:1 efficient (maybe less). So the specifications are critical, treat a heat pump as a boiler and it will be problematical.
I've fitted a few combination systems of my own design that complies with all regulations - which ensures that underfloor water is at low temperatures (for efficiency) - hot water via a diverting valve for baths is much less efficient. It's very time consuming to install and needs extra pumps, a large heat exchanger and some controls.
Hence I have now switched to providing two separate heat pumps, one for underfloor and one for hot water (actually a small heat pump on top of a 300 litre cylinder). The overall cost to the customer is the same, the running costs are much the same - and it's much easier for me.
Basic fundamental of a heat pump - the closer the temperatures you are pumping from/to, the higher the efficiency. For example, 10c outside, heating water from 25 up to 30c for underfloor and the system could be 5 or 6:1 efficient.
-5 outside - and you are using a heatpump to take water from 50-60c for radiators. Perhaps 2:1 efficient (maybe less). So the specifications are critical, treat a heat pump as a boiler and it will be problematical.
I've fitted a few combination systems of my own design that complies with all regulations - which ensures that underfloor water is at low temperatures (for efficiency) - hot water via a diverting valve for baths is much less efficient. It's very time consuming to install and needs extra pumps, a large heat exchanger and some controls.
Hence I have now switched to providing two separate heat pumps, one for underfloor and one for hot water (actually a small heat pump on top of a 300 litre cylinder). The overall cost to the customer is the same, the running costs are much the same - and it's much easier for me.
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