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4b Results of the literature review page 3

Heating Option 15: Heat pump

Nature of fuel/energy source

Electricity

Availability of fuel/energy source

Usually readily available but may be subject to shortages at times of peak demand.

Fuel/energy consumption

35-40 kWh/100 kWh delivered.

Efficiency of conversion of energy to heat

220-300% of delivered energy at point of use but full fuel-cycle efficiency will be lower when generation and transmission losses are considered.

Inverter models show greater efficiency than non-inverter types.

Efficiency is dependent on outside air temperature. Cooler outside air will lower the co-efficient of performance of a heat pump with the result that it is more efficient in warmer regions (such as Zones 1 and 2, as defined by the Energy Efficiency and Conservation Authority).

Typical operating costs

Ministry for the Environment: 3.7–7.3 cents/kWh

Christchurch City Council: 5–10 cents/kWh

Own calculations:

  • Standard rate: 6.5–9 cents/kWh (Meridian Energy, Christchurch)
  • There will also be a fixed connection charge (eg, 63.9 cents/day Meridian Energy, Christchurch).
  • These costs are based on Meridian tariffs for Christchurch; the standard rate is based on the Anytime tariff. Note that a cheaper Economy tariff is also available but supply to some appliances can be interrupted under this agreement so it might not be suitable for all heating applications. The tariffs used for these calculations offer a 10% discount for prompt payment, but this has not been applied to the operating costs presented here.

Typical capital costs

Approximately $2,000–$2,500 for small (< 3 kW) units.

Approximately $2,500–$3,000 for medium (3–5 kW) units.

Approximately $3,000–$3,500 for large (5–7 kW) units.

The above costs are based on single-outlet heat pumps.

Whole house split-ducted options typically range from $6,000 to $8,000.

Heating capacity

3 kW-12 kW (typically 3–6kW for a single-outlet heat pump, with larger models having two or more heat outlets).

Nature of the heat (radiant, convection, etc.)

Convection

Fuel/energy handling issues

None

Convenience of use

Easy

Ease of heat control

Usually thermostatically controlled.

Heat pumps can also be programmed to automatically switch on at a preset time of day.

Effectiveness of heat transfer

Good

Heat-up rate

Moderate/fast.

Ability to heat whole house vs single room

Good if designed/sized appropriately.

Particulate emissions

None at point of use, but electricity generation will produce particulate emissions when electricity supplied from coal- and gas-powered generators.

Greenhouse gas emissions

Other emissions

Health and safety issues in the home (eg, indoor emissions and moisture)

None

Embodied energy

Steel; plastic; copper.

Special features

Can achieve greater than 100% efficiency.

Risks associated with this option

Rising electricity prices.

Seasonal constraints on electricity supplies.

General comments

They need to be installed correctly - determined by whether heating or cooling is the main use, as well as optimum siting of both the outdoor and indoor units.

Inverter heat pumps are more efficient than non-inverter models due to the use of electronics to alter the quantity of heat output, rather than simply having the heating on or off, as is the case for a conventional split-cycle unit.

It should be noted that heat pumps use a fan to circulate the air. This means there is some background noise when the appliance is operating.

Suitability for use with heat-transfer system

No

Heating Option 16: Ceiling heating - distributed

Nature of fuel/energy source

Electricity

Availability of fuel/energy source

Usually readily available but may be subject to shortages at peak demand times.

Fuel/energy consumption

80-100 W/m2

100 kWh/100 kWh delivered.

Efficiency of conversion of energy to heat

100% of delivered energy at point of use, but full fuel-cycle efficiency will be lower when generation and transmission losses are considered.

Typical operating costs

Christchurch City Council: 6-20 cents/kWh

Own calculations:

  • Standard rate: 19.5 cents/kWh (Meridian Energy, Christchurch).
  • There will also be a fixed connection charge (eg, 63.9 cents/day Meridian Energy, Christchurch)
  • These costs are based on Meridian tariffs for Christchurch; the standard rate is based on the Anytime tariff. Note that a cheaper Economy tariff is also available but supply to some appliances can be interrupted under this agreement so it might not be suitable for all heating applications. The tariffs used for these calculations offer a 10% discount for prompt payment but this has not been applied to the operating costs presented here.

Typical capital costs

$50–$80/m2

Heating capacity

80-100 W/m2

Nature of the heat (radiant, convection, etc.)

Radiant

Fuel/energy handling issues

None

Convenience of use

Easy

Ease of heat control

Timer and thermostatically controlled.

Effectiveness of heat transfer

Good

Heat up rate

Fast

Ability to heat whole house vs single room

Yes if designed/sized properly.

Particulate emissions

None at point of use, but electricity generation will produce particulate emissions when electricity supplied from coal- and gas-powered generators.

Greenhouse gas emissions

Other emissions

Health and safety issues in the home (eg, indoor emissions and moisture)

None

Embodied energy

Foil

Special features

Risks associated with option

Rising electricity prices.

General comments

Only suitable for new houses.

Suitability for use with heat-transfer system

No

Heating Option 17: Ceiling heating - radiant

Nature of fuel/energy source

Electricity

Availability of fuel/energy source

Usually readily available but may be subject to shortages at times of peak demand.

Fuel/energy consumption

110 kWh/100 kWh delivered.

Efficiency of conversion of energy to heat

90% of delivered energy at point of use, but full fuel-cycle efficiency will be lower when generation and transmission losses are considered.

Typical operating costs

Christchurch City Council: 6–20 cents/kWh

Own calculations:

  • Standard rate: 19.5 cents/kWh (Meridian Energy, Christchurch)
  • There will also be a fixed connection charge (eg, 63.9 cents/day Meridian Energy, Christchurch).
  • These costs are based on Meridian tariffs for Christchurch; the standard rate is based on the Anytime tariff. Note that a cheaper Economy tariff is also available, but supply to some appliances can be interrupted under this agreement so it might not be suitable for all heating applications. The tariffs used for these calculations offer a 10% discount for prompt payment but this has not been applied to the operating costs presented here.

Typical capital costs

$100–$250

Heating capacity

250 W

Nature of the heat (radiant, convection, etc.)

Radiant

Fuel/energy handling issues

None

Convenience of use

Easy

Ease of heat control

Instant control

Effectiveness of heat transfer

Good

Heat-up rate

Fast

Ability to heat whole house vs single room

No

Particulate emissions

None at point of use, but electricity generation will produce particulate emissions when electricity supplied from coal- and gas-powered generators.

Greenhouse gas emissions

Other emissions

Health and safety issues in the home (eg, indoor emissions and moisture)

Heat can be intense at source - heater must be located to minimise risk of burning/combustion.

Embodied energy

Glass; copper; filament materials.

Special features

Risks associated with this option

Rising electricity prices.

Seasonal constraints on electricity supplies.

General comments

 

Suitability for use with heat-transfer system

No

Heating Option 18: Diesel heater

Nature of fuel/energy source

Diesel

Availability of fuel/energy source

Widely available, although additional charges may be made for home delivery in some regions.

Fuel/energy consumption

10 L/100 kWh

Efficiency of conversion of energy to heat

65-80%

Typical operating costs

Ministry for the Environment: 8.4- 9.8 cents/kWh

Christchurch City Council: 8-10 cents/kWh

Own calculations: 10-12.5 cents/kWh

Typical capital costs

$3,500-$4,500

Heating capacity

7 kW-12 kW

Nature of the heat (radiant, convection, etc.)

Mainly convection, but also some radiant component.

Fuel/energy handling issues

Requires fuel storage tank; fuel oil can be messy.

Convenience of use

Easy

Ease of heat control

Good

Effectiveness of heat transfer

Good

Heat-up rate

Slow

Ability to heat whole house vs single room

Can achieve moderate heating of whole house if heat can be distributed. Good air/heat circulation is required to prevent overheating in the vicinity of the heater.

Particulate emissions

PM10: 0.3 g/kg; 6.5 mg/MJ

Greenhouse gas emissions

CO2: 3200 g/kg; 80,200 mg/MJ

SOx: 4.0 g/kg; 87 mg/MJ

NOx: 2.0 g/kg; 43 mg/MJ

Other emissions

CO: 0.5g/kg; 10.8 mg/MJ

PM2.5: 0.2g/kg; 4.3 mg/MJ

Health and safety issues in the home (eg, indoor emissions and moisture)

None apparent.

Embodied energy

Steel; ceramics; transport of fuel.

Special features

Diesel heaters can be used to heat wetbacks, but this reduces the efficiency of heat transfer for space heating and may also overheat the water.

Risks associated with this option

Availability of fuel supply; rising oil prices.

General comments

Suitability for use with heat-transfer system

Yes

Heating Option 19: Oil-fired central heating

Nature of fuel/energy source

Diesel

Availability of fuel/energy source

Widely available, although additional charges may be made for home delivery in some regions.

Fuel/energy consumption

7-9 L/100 kWh

Efficiency of conversion of energy to heat

90%

Typical operating costs

Own calculations: 9 cents/kWh.

Typical capital costs

$7,000–$15,000 depending on size of house and inclusion of water heating.

Heating capacity

15-35 kW.

Nature of the heat (radiant, convection, etc.)

Radiant and natural convection.

Fuel/energy handling issues

Diesel is usually stored in tanks of 500 L or larger. The fuel is piped to the boiler.

Convenience of use

Requires hardly any user input and runs entirely automatically. Maybe service once a year.

Ease of heat control

Controllability is part of the design. Systems can be programmed to come on to heat up before the household rises and go off immediately the room reaches a set temperature.

Each room can be set to a different temperature.

Effectiveness of heat transfer

Good: use of water as the heat-transfer medium is the best form of heat transfer. A central heating system is designed so that the output of the radiators matches the heat loss of the room.

Heat-up rate

Fast: a large heat output enables very rapid heat-up rates. Can also be programmed to come on without manual input.

Ability to heat whole house vs single room

It is designed to be a whole-house system and is most cost-effective as a whole-house and hot-water system.

Particulate emissions

PM10: 0.3 g/kg

Greenhouse gas emissions

CO2: 3200 g/kg

SOx: 4.0 g/kg

NOx: 2.0 g/kg

Other emissions

CO: 0.5 g/kg

PM2.5: 0.2 g/kg

Health and safety issues in the home (eg, indoor emissions and moisture)

Generally most appliances have balanced flues, meaning no interchange of internal air and combustion air.

Even distribution of heat means that damp and associated mould are eliminated from homes with central heating.

Embodied energy

Special features

High efficiency due to combustion efficiency and controllability.

Can provide all the heating and hot water in the house with virtually no need for electricity or supplementary fuel.

The heat distribution system lasts for decades. Only the boilers and pumps need replacing every 15-20 years.

Easy to change fuels by just changing the boiler.

Very quiet.

No drafts.

Very high heat output with even heat distribution.

Can go to maximum heat output easily and conveniently.

Can add significant value to a home.

Risks associated with this option

Availability of fuel supply.

General comments

This is a very high quality building service, which is standard throughout the world in countries that need heating in the winter.

Although it has a high initial cost, the long term benefits and high quality of heating have made it one of the world's most popular heating systems among those that can afford it.

Suitability for use with heat-transfer system

N/A

Heating Option 20: Wood pellet-fired central heating

Nature of fuel/energy source

Wood pellets

Availability of fuel/energy source

Pellets - local supplies; limited to certain areas.

Fuel/energy consumption

24-26 kg/100kWh delivered.

Efficiency of conversion of energy to heat

90-92%

Typical operating costs

7.5 cents/kWh.

Typical capital costs

$15,000-$20,000 depending on size of house.

Lower price is for heating to all rooms; the more expensive option also provides water heating.

Heating capacity

15-35 kW.

Nature of the heat (radiant, convection, etc.)

Radiant and natural convection.

Fuel/energy handling issues

Pellets are usually in a hopper, which needs refilling every few days - depending on the weather and heat load. Can get much larger hoppers for many months' supply.

Convenience of use

Pellets require topping up and ash requires occasional removal.

Ease of heat control

Controllability is part of design. Systems can be programmed to come on to heat up before the household rises and go off immediately the room reaches a set temperature.

Each room can be set to a different temperature.

Effectiveness of heat transfer

Good: use of water as the heat-transfer medium is the best form of heat transfer. A central heating system is designed so that the output of the radiators matches the heat loss of the room.

Heat-up rate

Fast: large heat output enables very rapid heat-up rates. Can also be programmed to come on without manual input.

Ability to heat whole house vs single room

It is designed to be a whole-house system and is most cost-effective as a whole-house and hot-water system.

Particulate emissions

PM10: 0.4 g/kg

Greenhouse gas emissions

SOx: 0.2 g/kg

NOx: 5.2 g/kg. Note that this is a relatively high level, but it is based on the only available data (Scott 2004). Scott uses data derived from work carried out in 1998, which may well overstate the level of NOx emissions from a current model pellet fire. It would be useful to test a current model for NOx emissions.

CO2: 1480 g/kg, but considered neutral.

Other emissions

CO: 15 g/kg

PM2.5: 1.5 g/kg

Health and safety issues in the home (eg, indoor emissions and moisture)

Generally most appliances have balanced flues, meaning no interchange of internal air and combustion air.

Even distribution of heat means that damp and associated mould are eliminated from homes with central heating.

Embodied energy

Special features

High efficiency due to combustion efficiency and controllability.

Can provide all the heating and hot water in the house with virtually no need for electricity or supplementary fuel.

The heat distribution system lasts for decades. Only the boilers and pumps need replacing every 15-20 years.

Easy to change fuels by just changing the boiler.

Very quiet.

No drafts.

Very high heat output with even heat distribution.

Can go to maximum heat output easily and conveniently.

Can add significant value to a home.

Risks associated with this option

Limited sources of fuel supply.

General comments

This is a very high quality building service, which is standard throughout the world in countries that need heating in the winter.

Although it has a high initial cost, the long term benefits and high quality of heating have made it one of the world's most popular heating systems among those that can afford it.

Pellet-fuelled central heating is established in other countries but has yet to become widespread in New Zealand.

Suitability for use with heat-transfer system

N/A