Introduction to Heat Pumps Chris Dale Director Danfoss Heat Pumps UK
22nd march 2011
Regen SW
HPA The Heat Pump Association, formed in 1995, is a member of FETA (Federation of Environmental Trade Associations). Objectives
To promote the use of heat pumps through
education, public relations and lobbying. To increase public awareness of new technology. To provide application advice to potential designers and end users 22nd march 2011
Regen SW
Agenda • • • • •
• • • •
What is a heat pump? How do they work? Heat Pump types Heat Pumps and their applications Specifying Heat Pumps
Air or Ground Source? Running costs and carbon emissions RHI Seeking advice
22nd march 2011
Regen SW
What is a Heat Pump? •
A heat pump is a device that is capable of extracting low grade heat from one location, and upgrading it for use in another area.
•
It works by extracting heat from the ground, air, or water and upgrading the temperature in order to heat the dwelling, and/or domestic hot water store.
22nd march 2011
Regen SW
Laws of Thermodynamics 1st.
Energy can be neither created nor destroyed. It can only change form.
2nd.
Heat can spontaneously flow only from a highertemperature region to a lower-temperature region, but not the other way around.
22nd march 2011
Regen SW
How does a heat pump work? A mixture of water and anti freeze solution known as Brine circulates in a collector and draws low temperature energy from the ground, air, bedrock or water.
Compressor Heating supply Condensor
Evaporator
Collector supply
Collector return
Heating return Expansion valve
22nd march 2011
Regen SW
How does a heat pump work? Heating supply
Collector supply
High pressure – Hot gas
Low pressure gas
Collector return
Heating return Compressor
Evaporator
Condensor
Expansion valve Filter dryer
Low pressure - cool liquid
22nd march 2011
Regen SW
Inside the heat pump Condensor
Evaporator {First stage heat exchanger}
{Second stage heat exchanger}
Brinepump
Compressor
Expansion valve 22nd march 2011
Regen SW
Types of heat pump Direct expansion ASHP
Commercial GSHP
Domestic GSHP
Brine to water ASHP
22nd march 2011
Regen SW
Ground Source
Horizontal ground loop system
Borehole system 22nd march 2011
Regen SW
Air Source
Direct expansion ASHP
Brine to water ASHP
22nd march 2011
Regen SW
Water Source
Closed loop - water source
Open loop – water source
22nd march 2011
Regen SW
Ground Source or Air Source? Drilling rig
Manifold and chamber installation
Horizontal trenching 22nd march 2011
Regen SW
Typical heat pump applications Schematic: GSHP for heating and hot water
characteristics and requirement. Location Source/Geology
Output Estimated collector size Energy use Estimated energy
savings
22nd march 2011
Regen SW
Sizing the heat pump There are a number of important factors to take into consideration when sizing a heat pump! For example: • geographical location • size of building (heated floor area) • type of building • construction materials • age of building • hot water requirement • other heat sources
22nd march 2011
Regen SW
Low temperature Distribution
The efficiency of the heat emitter is directly related to it’s surface area. A standard radiator system designed for use with a gas or oil boiler has a small surface area in comparison with the area it is attempting to heat. Therefore temperatures around 80°C may be required with such systems. Upgrading or over sizing the radiator system can allow the system to run at the lower temperatures With under floor heating there is a much greater surface area available, and therefore significantly lower temperatures can be supplied
22nd march 2011
Underfloor Heating
Efficiency
Low surface temperature (LST) radiators
Oversized Radiators
Distribution Temperature
Regen SW
Renewable Heat Incentive
Commercial Installations GSHP tariffs set from 1st July ○ < 100kW @ 4.3p/kwh ○ > 100kW @ 3p/kwh
Domestic Domestic RHI Premiums from 1st July. ○ Likely levels of support at £1250 for GSHP & £850 for ASHP
Domestic RHI from Oct 2012 22nd march 2011
Regen SW
Running costs and carbon emissions
Based on a typical UK installation example, we can calculate comparative operational savings in terms of monetary cost, kWhs and CO2 emissions:
Location - Sheffield
Building - 200m2, with a heat loss of 40w/m2, suggesting an annual energy requirement of 24,649kWh (including 4000 kWh for hot water and 166kWh for additional electric heating)
Heat pump – Danfoss GSHP DHP-Opti Pro (8kW) with a 400m horizontal ground loop. Giving a seasonal performance factor of 4:32
Fuel
Price/kWh (est.)
Nat gas
0.04p
985.96
301
LPG
0.08p
1,971.92
1,287
Oil
0.07p
1,725.43
1,040
7.54
4.46
Electricity
0.12p
2,957.88
2,273
13.30
10.20
22nd march 2011
Annual cost (£)
Annual saving (£)
Regen SW
Annual CO2 (tonnes) 5.67 6.6
Annual saving CO2 (tonnes) 2.57 3.5
Seeking Advice Microgeneration Certification Scheme Heat Pump Association