Air Source Heat Pumps

NaffSlack

Sorry, its a electric only building. 2 bed basement flat.

They are installing a 210 litre unvented indirect hot water cylinder and a 18kw air soursed heat pump and installing central heating piepwork through the property with wet raditors. Also a Magnaclean unit to work against iron oxide particles and a small booster boiler for the colder months to top up the heat.

lovesgshp

18Kw? How large is the flat? Seems rather OTT unless you have around 300 sq mtrs to heat.

NaffSlack

quite small, 2 bed flat

lovesgshp

NaffSlack wrote: »

quite small, 2 bed flat

Think 18Kw is by far too much and plus a booster tank. They could have included the DHW tank with a immersion heater.
Ask for the thermal loading calculation from them, or get a second quotation.

NaffSlack

i emailed the guy and this was his reply

"On the surface an 18kw ASHP (Air sourced heat pump) and a 6kw Electric boiler does seem OTT. The ratings for all ASHPs are quoted based on an outside temp of 20 degC, as the temperature drops so does the amount of heat it can provide. At –5degC this ASHP will provided 8.5kW of heat which is how much you need for central heating and the hot water combined. At temperatures below 5degC, under certain circumstances, ice can form on the vanes of the heat exchanger reducing its ability to produce heat. When this happens the ASHP then tells the electric boiler to provide the heat to the property whilst the ASHP briefly goes into defrost mode, which melts the ice on the vanes. Then the ASHP returns to its normal mode and shuts off the electric boiler. This a requirement of the manufacturer.

We also add controls into the system that, if the heat pump is not providing enough heat for the system, ie below –5degC, the electric boiler comes on and adds to the heat from the ASHP to provide sufficient heat for the system to work properly.

The electric boiler use will be infrequent, but necessary, to provide the right amount of heat required but with the maximum efficiency"

lovesgshp

NaffSlack wrote: »

i emailed the guy and this was his reply

"On the surface an 18kw ASHP (Air sourced heat pump) and a 6kw Electric boiler does seem OTT. The ratings for all ASHPs are quoted based on an outside temp of 20 degC, as the temperature drops so does the amount of heat it can provide.
Don't know where this guy is coming from, but ASHP's are based on 7C input to either 35 or 45C output European standard EN14511.

At –5degC this ASHP will provided 8.5kW of heat which is how much you need for central heating and the hot water combined. At temperatures below 5degC, under certain circumstances, ice can form on the vanes of the heat exchanger reducing its ability to produce heat. When this happens the ASHP then tells the electric boiler to provide the heat to the property whilst the ASHP briefly goes into defrost mode, which melts the ice on the vanes. Then the ASHP returns to its normal mode and shuts off the electric boiler. This a requirement of the manufacturer.

We also add controls into the system that, if the heat pump is not providing enough heat for the system, ie below –5degC, the electric boiler comes on and adds to the heat from the ASHP to provide sufficient heat for the system to work properly.

The electric boiler use will be infrequent, but necessary, to provide the right amount of heat required but with the maximum efficiency"

Can you tell me what make and model ASHP this is referring to?

paceinternet

Something for you to consider concerning how you would run the system.
1. Since it would be radiators, do check the sizings are good at an economical flow temperature.
2. Would you expect to run it for long continuous periods of time, or for timed periods when you are in the property? Heat pumps do not normally have excess capacity to provide quick warm up when a time clock switches them on from cold. So, the oversized system offered to you may be suitable for your lifestyle. But, it would also be considerably oversized during less cold times of the year, and you need to be advised that it can economically deal with that situation as well. I mean is it inverter driven, or buffer store or ?

lovesgshp

Naffslack
Why not try this calculator and see what it suggests?
http://www.energysavingtrust.org.uk/business/Business/Housing-professionals/Interactive-tools/Domestic-heating-sizing-wizard/Whole-house-boiler-sizing-Tool

lovesgshp

jeepjunkie wrote: »

We also looked into ASHPs as friends have one.

Our friends system is not complete yet so can't really comment but initial reaction was it's not that warm given the hideous cost.

Wish we had not bothered as the quotes differ wildly by as much as £10k plus which gives zero confidence. Lot's of inexperienced companies jumping on the ASHP bandwagon... Even when you find an installer you can trust the system seems specced by holding a finger in the air! Despite incentives the initial costs, running costs and expected lifespan makes no sense. I'd be dead by the time it paid for itself...

Bascally you need sily amounts of insulation in a custom built house to make it work whereas a woodburner/multi-fuel stove can heat my old vitorian pile with basic insulation no probs. So that's the answer for us a second stove but connected to our existing radiator system for peanuts :-)

Jeepjunkie
Agree with you totally re the companies jumping on the bandwagon. We will not install a system here without a total thermal analysis of the property. As an example, just recently from our basic questionnaire, we came to a 17kw GSHP for a 300+ sq mtr property, the later thermal analysis came in @ 22Kw, so we adjusted the estimate for the client, as we will not install without it, plus it is a regulation here in Italy. We only hold fingers up in the air on the initial quote, but will not proceed until we get a thermal quote.

From that customer received this week quoted:
Everything seems to be working a treat, we are delighted with it all. We got our first bill today for a month, considering we had to put it on pretty high at the beginning and assuming the cost will be much less in the summer months at euro 311 I think not bad. We should achieve about a 50% saving compared to the gas (LPG). It is also working well with the timer so we have it working as much as possible in the night and that seems to have helped since the cost is split in the three phases of the day. We really like the way it heats and maintains the warmth at a lower temperature than with the gas.

Please remember energy bills are much higher here in Italy
We are IGSHPA, The Association of Energy Engineers and GeoExchange members. With IGSHPA we have to be re-certified every 2 years.

lovesgshp

Don't know how this will come out, but an example of the English questionnaire we use

GEOTHERM IVT ITALIA – OFFER QUESTIONNAIRE


Dear Sir / Madam
Thank you for your interest in our renewable energy systems. Geotherm IVT Italia systems are constructed with lots of care during project planning and management, so that the installation can be completed quickly. The system is easy to use, efficient, reliable and long lasting through our carefulness for the single project and the best materials you can find on the market. Geotherm IVT Italia is the company with the most experience in Italy, for ground source heat pumps and high efficiency air-water heat pumps, and thats why it has the leadership for both materials and service. That is to say reliability, service and customer satisfaction. Please fill in this questionnaire so that we have all the information that we need to give you an offer.

Architectural Data:

A) Your house is:
a1) □ An existing house built more or less in the year __________
a2) □ A new house
a3) □ A restored house
If you have stated a2 or a3 please state when the restoration work starts:
- currently I just have the project, Works start on ___________
- currently I am building the house, it is at this stage: _____________________
_________________________________________________________________

Is your house:
b1) □ An apartment
b2) □ A detached house
b3) □ A semi-detached house

C) Your house size is _________ m2 (sum every floor to be heated) and its volume is about _________m3 How many floors?_____


Thermal Loads:

D) Do you know the thermal loads (in watt) at design conditions for your building (according italian law 10/91 and 192/2005)?
d1) □ NO (in this case we will do an estimate; we suggest you obtain an analysis of the thermal loads from a technical engineer or from our company)

d2) □ YES. In this case, Please read your report and tell us : Watt (Watt Heating load from the building to the outside at local design conditions. (attention: they are not the same as the boiler capacity): Thermal loads Watts ____W + thermal loads for ventilation____W = Total thermal loads=____W
Please if available send us climate data that are stated in your report about your location.


Heating System:

E) We can consider now the heating system for your building:
e1) What type of fuel is locally available?
□ natural gas, □ LPG gas, □ oil, □ pellet/lwood

Is the internal heating system installed?
e2) □ NO
In this case, what kind of heating are you considering?
□ radiant floor, □ radiators, □ radiant floor, □ air/fan consoles

e3) □ YES
In this case, what kind of heating is installed?
□ radiant floor, □ radiators, □ radiant floor, □ air/fan consoles
What kind of furnace is installed?
□ natural gas, □ LPG gas, □ oil, □ pellet/wood, □ not installed yet,

How old is this furnace?________years

F) Sanitary hot water. How many people will live in the building_________persons
T: □ shower, □ bath tub, □ whirpool shower, □ whirpool shower,
□ We utilize mainly the shower
□ We utilize the bath tub more than once a week

Property:

G) Consider your garden property, what do you think about the kind of soil? (it possible to select more than one choice)

□ clay based (plastic, yellow and compact ground)
□ sand and lime (sand alternating with a layer of lime)
□ rock
□ maily gravel

If you dig at least a metre deep, your ground is?:
□ humid, □ dry, □ full of water

According to your knowledge, the ground aquifer water level is_______m deep.

H) Your garden or land property is_________ m2 wide

Please design in a simple way, with the measures: planimetry of the land with the position of the house, north side (arrow), trees, underground electric, gas and water lines, entrance and main roads, other buildings. Please write if the land is flat or there are some slopes. You can add to this questionnaire some designs or Autocad files about your property.


=........meters


Project and personal data:

I) Please fill this area with your personal data:
You are:
□ the end customer
□ the engineer or architect for this project
□ the installer. Firm data:....................................................................................

Name:..................................................... Surname:........................................................
Address:.........................................................................................................................
Town.....................................................................code..........................Prov.................
Tel:..................................................... Fax:............................................................
Mobile:.....................................................email:..........................................................

The boilding is located in (Town and Province):..............................................
Altitude:............................meters

I AM INTERESTED TO A FREE OFFER OF (choose a system):

□ a Geotherm system with an IVT ground source (geothermal) heat pump

□ a Geotherm system with an IVT Optima air-water heat pump
□ with the complete substitution of the existing furnace
□ connected to the existing furnace
Date:.......................................

SEND THE FILLED QUESTIONNAIRE TO:
GEOTHERM SRL IVT ITALIA – UFFICIO TECNICO
V. S. LORENZO 60 A 37038 SOAVE (VR) – fax 045 6103612
email: info@geotherm.it

Informativa in materia di protezione dei dati personali ex art. 13 D.lgs. 196/2003

Gentile Signore/a, Desideriamo informarLa che il D.lgs. n. 196 del 30 giugno 2003 ("Codice in materia di protezione dei dati personali") prevede la tutela delle persone e di altri soggetti rispetto al trattamento dei dati personali. Secondo la normativa indicata, tale trattamento sarà improntato ai principi di correttezza, liceità e trasparenza e di tutela della Sua riservatezza e dei Suoi diritti. Ai sensi dell'articolo 13 del D.lgs. n.196/2003, pertanto, Le forniamo le seguenti informazioni: 1. I dati da Lei forniti verranno trattati per le seguenti finalità: analisi di fattibilità tecnica e preventivo per impianto tecnico 2. Il trattamento sarà effettuato con le seguenti modalità: manuale ma anche con l'ausilio di mezzi elettronici, direttamente e/o tramite terzi delegati 3. Il conferimento dei dati è facoltativo e l'eventuale rifiuto di fornire tali dati non ha alcuna conseguenza. 4. I dati non saranno comunicati a terzi se non per usi strettamente connessi alla realizzazione del preventivo e dell’eventuale progetto. 5. Il titolare del trattamento è Geotherm srl con sede in via Argine sx n.18, Bovolenta (PD)6. Il responsabile del trattamento è Geotherm srl con sede in via Argine sx n.18, Bovolenta (PD)