Advice needed on ASHP

[FB.]

Last comment I heard from Patrick Allcorn (heid yin of domestic RHI) of DECC was the intention was to include on-grid areas but that because gas is available, the RHI would not be all that an attractive proposition.

With the horror stories surrounding condensing gas boilers - breakdowns, maintenance and expenses - I'd rather take my chances with a heat pump!

I would have thought that houses like mine, in need of a new/improved heating system (or at least a boiler) ought to be among the first to have retro-fits of new technology for trials. Solar and ASHP on a middle-aged property would be an inspirational push into renewables.

But if they want me to reduce my carbon emissions, it would be crazy to encourage me to keep burning the gas. But if gas ends up being the cheaper option then I'll carry on chugging out the CO2 with the old inefficient boiler (75% efficient when new, probably 65% now).

 

[FB.]

The RHI you might get will be based on a deemed amount of heat your house requires calculated with RdSAP-style software. The kWh you actually use will be irrelevant. And it is still possible that DECC will decide that RHI is not going to be available for those on the gas grid.

It would be a shame to encourage me to keep using gas (and emitting CO2) when there's the prospect of adding a lower-emission technology, particularly so as I would be eager to have a heating system reconstruction during summer 2013.

But as per my previous post: my tired old boiler can keep pouring out the CO2 if they want to make my life difficult.

For what it's worth, I think I'm a low-user.
4-bed detatched, used 10810kWh gas (about £550*) and 3139kWh electric (about £450) in 2011, according to my bills.

*Average gas bill reported to be £650 during 2011.

 

[jason121]

Mono bloc are good, no boiler inside, the heat exchange built in the main unit, you will need buffer tank and proberly a new hot water tank. Panaonsonic TCAP are good maintain full KW rating down to -15

Change radiators to low temp ones run them at 45 degrees cheap heating. Hopefully RHI will cover 90% of install cost over 7 years

 

[sambotc]

Star rating relates to the size of the radiator compared to the heat requirement. The bigger the radiator the lower the flow temp can be, lower the flow temp and heat pump doesn't have to work as hard meaning less electric used and a more economical system.

Solely reducing the flow temp will mean you have cold people! Also remember that lower the flow temp and you increase the warm up times, opening a door for 10 seconds in winter could take an hour to recover from.

 

[jason121]

the RHI want a SPF of 3 before they will pay out the higher rate

 

[sambotc]

With the horror stories surrounding condensing gas boilers - breakdowns, maintenance and expenses - I'd rather take my chances with a heat pump!

I would have thought that houses like mine, in need of a new/improved heating system (or at least a boiler) ought to be among the first to have retro-fits of new technology for trials. Solar and ASHP on a middle-aged property would be an inspirational push into renewables.

But if they want me to reduce my carbon emissions, it would be crazy to encourage me to keep burning the gas. But if gas ends up being the cheaper option then I'll carry on chugging out the CO2 with the old inefficient boiler (75% efficient when new, probably 65% now).

I decent condensing boiler installed professionally by someone who knows what they are doing (and a lot don't believe me) should be fairly reliable. A lot of the horros stories come from poor installations and early condensing boilers.

 

[sambotc]

forget the RHI. You are installing a system that needs to be able to cope with the properties heat load without using a shed load of electric. The star rating reflects the CoP which will indicate how efficient the system will be. Chucking in a system on the basis of RHI payments is not how it is intended and is heading towards failure. These aren't 'luxury' items like a P.V array. Mess it up and people are going to get cold or run up huge electricity bills.

This is the problem with renewables and the tariff they offer. Everyone has there eye balls stuck on the financial gain rather than their intended purpose.

As a heating engineer I can see this heading down the same road as the FiT's, and actually see the reasons for the delays.

 

[FB.]

How reliable are ASHP's and how easy are they to get repaired - especially relative to the ease and speed of getting someome to repair a gas boiler.

What's the realistic lifespan of an ASHP and what kind of warranty and ongoing maintenance and repair costs are likely?
With a motor running many hours per day, for several or more months per year, that's a lot of wear on a major moving part.

 

[Earthstore]

Your fridge and freezer run 24 hours per day, 365 days per year, how long do they last?
It is the same technology...

 

[FB.]

I decent condensing boiler installed professionally by someone who knows what they are doing (and a lot don't believe me) should be fairly reliable. A lot of the horros stories come from poor installations and early condensing boilers.

In my case, though, even the best boiler would struggle to do the job as the rads are under-spec in the major living area.
Go out for the day and leave the heating off, to find it dropped to around 17'C while out and takes two hours to get back up to 21'C.
Rads are hot (too hot to touch), but just not big enough to give off enough heat.
Complete system re-design would be a good idea - and I'd love to take the opportunity to try a well-designed ASHP system, if only to serve as a warning to others!

 

[jason121]

forget the RHI. You are installing a system that needs to be able to cope with the properties heat load without using a shed load of electric. The star rating reflects the CoP which will indicate how efficient the system will be. Chucking in a system on the basis of RHI payments is not how it is intended and is heading towards failure. These aren't 'luxury' items like a P.V array. Mess it up and people are going to get cold or run up huge electricity bills.

This is the problem with renewables and the tariff they offer. Everyone has there eye balls stuck on the financial gain rather than their intended purpose.

As a heating engineer I can see this heading down the same road as the FiT's, and actually see the reasons for the delays.

I think your missing the point
if the the heat loss of a building is 9kw the heat pump will be sized according the area conditions and degree data, If your MCS heat pump installer you will know about the emitter guide that you must show the customer, stating his star rating for property, including this in the quote. The idea of reducing operating temp is to reduce running costs of the heat pump by doing this either install smart rads or oversize rads or LTR's
Most heat pumps only produce 55 degress thats the idea behind the emitter guide and altering RADS

 

[jason121]

All you need to do is size the heat loss in the property using the u values of the house, there is a spread sheet on the MCS web site and webminar explaining all about it,this gives you a estimated guide of the running costs and sizing of heat pump. Next step would be sizing radiators rooms.

 

[FB.]

This is the problem with renewables and the tariff they offer. Everyone has there eye balls stuck on the financial gain rather than their intended purpose.

As a heating engineer I can see this heading down the same road as the FiT's, and actually see the reasons for the delays.

My view on FiT's is that they should be used to get a renewable technology established as a result of larger numbers of installations leading to knowledge, experience, economies of scale and cost savings which subsequently bring the costs down for everyone else.,
But the FiT should not be so generous that people can retire on it!

So someone like me - soon in need of at least a new boiler and ideally a redesigned heating system - could be persuaded to help a budding industry if the cost or benefits of ASHP stack up well against fitting another gas boiler.
If ASHP works out only fractionally cheaper than gas, I'll take it, whether subsidised or not. The subsidy will simply help to kickstart things. Let's just hope that if prices come down (as was the case for solar) that they don't leave FiT's too high for too long which results in another boom-bust.

 

[jason121]

PAGES from the consultation paper
Option 2: Varying RHI Tariffs for Heat Pumps so that they are Linked to the SPF Measured in the Metering and Monitoring Service Package.................................................................................. 71

Option 3: Introducing a Higher Seasonal Performance Factor (SPF) for Heat Pumps as an Eligibility Requirement for the RHI .............................................................................................. 72

 

[jason121]

218. As set out in Chapter 3, the EU sets minimum performance standards for heat pumps for them to be classified as renewable (articulated as a Seasonal Performance Factor (SPF)), and we intend to use a light-touch approach to enforce this by monitoring the Temperature Star Rating of the systems being installed. If installers are intentionally designing systems to perform poorly, we would take action to prevent them doing this. However, in order to ensure that heat pumps are performing as well as possible we could introduce a minimum level of performance that goes beyond what is required in the RED. For example, we could require a minimum SPF of 2.7 as an eligibility criterion. This could be based on the likely design space heating SPFs in the Heat Emitter Guide for Domestic Heat Pumps, which is part of MIS 3005, the MCS installer standard for heat pumps. Setting an SPF of this level is higher than the current EU minimum, which changes every year but is currently 2.5. However, it is lower than that claimed by many heat pump retailers and significantly lower than the SPF levels required by the Heat Pump Stimulus Programme in one of the EU’s largest markets for heat pumps – the German Federal Environment Ministry’s Marketanreziprogramm – which requires 3.5 for air source heat pumps and 3.8 for ground source heat pumps.