Heat Pumps:Save Money, Save Energy,

Save the Environment

Outline

1) Understand how a heat pump works.

2) Understand how we save energy.

3) How does this save us money?

4) End by discussing how heat pumps help

save the environment.

How a Heat Pump

Works

Energy Overview

Energy comes from many places:

- burning oil, flowing water, etc

Energy exists in many forms:

- heat, electricity, etc

Energy can be converted from one form to

another:

- electricity is used to produce heat, etc

Units

Watt = Basic unit of power (electricity)

Example: 60 watt light bulb uses 60 watts

Kilowatt = 1000 watts

KWh = # of kilowatts used over an hour

Examples

One 60 watt light bulb uses 0.06 KW and

uses 0.06 KWh after 1 hour.

Two 60 watt light bulbs left on for one hour

use 0.12 KWh.

One 60 watt light bulb left on for 2 hours

uses 0.12 KWh.

Another Unit

Btu = Basic energy unit (heat)

1 KWh = 3413 Btu’s

Heat Pumps are more efficient

since you get more energy out than

you put in.

Energy Flow of an Oil Burner

We only get out

what we put in.

Energy Flow of a Heat Pump

Pull extra heat from

the outside air.

Measure of Efficiency

COP = insBtu'

outsBtu'

Example

0.31000

3000COP

Moving heat: Heat Pump

1. Absorb heat in refrigerant.

2. Pump refrigerant inside house.

3. Eject heat from refrigerant.

How does a Heat Pump do it?

We must understand the Ideal Gas Law.

PV = nRT

P = Pressure

V = Volume

n = # of particles of gas

T = Temperature

R is a constant

PV = nRT

As pressure goes up,

temperature goes up.

Pressure Temperature

Refrigeration Cycle

Mini-Split Heat Pumps

Save Energy

Goal

Burn oil to produce heat

Question

What produces the most energy?

Two Choices

Burn Oil

at Power

Plant

Burn Oil

at

Home

Produce Heat

at Home

Produce

ElectricityProduce Heat

at Home

Assumptions

Oil burner at home is 80% efficient

Power plant is 30% efficient

Use a Heat Pump to convert electricity to heat with a COP of 3.4

Note: An average oil furnace is 80% efficient,

an average oil-burning power plant is 33% efficient,

transmission + distribution loss is 9%,

and the Fujitsu 9RLS mini-split heat pump has an

average COP of 3.4 when in used in Maine.

How Much Heat is Produced?

Option 1: Burn Oil at Home

1000 Btu Oil

80% Efficient

800 Btu Heat

How Much Heat is Produced?

Option 2: Burn Oil at Power Plant

1000 Btu Oil

30% Efficient

300 Btu Electricity 1020 Btu Heat

COP of 3.4

Which Choice is Better?

Using 1000 Btu of oil:

Burn Oil at

Home

Burn Oil at

Power Plant

800 Btu Heat

Produced

1020 Btu Heat

Produced

Choice 2

is 28%

Better!!!

Ultimately…

New power plants will be needed:

Gas Power Plants

Natural Gas – More Efficient

Electricity can potentially come from very efficient sources

Save Money

Question

Installing a Heat Pump:

How much money is saved?

Heating

Wherever they come from, you need Btu’s

to heat your home.

When it is colder, you need more Btu’s to

heat your home.

Heat pumps: more efficient when it’s

warmer out.

Oil Burners: more efficient when it’s

colder out.

Fact:

While the Heat Pump is Running,

it is Saving you Money

Limitations of Heat Pumps

The 9RLS Mini Split Heat Pump shuts off

at 5º F.

Heat Pump works best when you need the

least amount of heat.

How do we Calculate the Savings?

When is the Heat Pump

Running?

At some point,

the heat pump

puts out more

heat than is

needed.

Assumptions

Oil burner at home is 80% efficient

Price of electricity: $0.16 per KWh

Price of # 2 Heating Oil: $3.00 per gallon

# of Btu’s per gallon of # 2 Heating Oil

= 140,000 btu’s

9RLS Mini Split Heat Pump runs at full capacity

at 40 F and below.

Indoor temperature kept at 70 F.

Heat Pump Savings

Given:

Outdoor Temp = 5-10 F Temp of

lowest

efficiency

Average # Hours = 185 hours

Heat Pump Capacity = 8470 Btu per hour

Heat Pump COP = 2.82

Heat Pump Electricity Use

8470 Btu Conversion:

hour

KWh

Btu

KWh

hour

Btu

1

4817.2

3413

1

1

8470 Amount of heat

Produced per hour

hourperKWhhourperKWh

8800.082.2

4817.2

KWhhours

hour

KWh8.162

1

185

1

8800.0

Electricity use

per hour

Electricity Use

per year

Heat Pump Cost

05.26$16.0$

1

2.168

KWh

KWh

Cost for heating over an average year (at a Temp of 5-10 F):

Oil Use

8470 Btu Conversion:

Cost per hourhouroilgalBtu

oilgal

hour

Btu

1

2269.0$

1

00.3$

112000

1

1

8470

oilgalperBtuefficiencyoilgal

Btu112000%80

1

140000

Oil Cost

97.41$1851

2269.0$hours

hour

Cost for heating over an average year (at a Temp of 5-10 F):

Savings

$41.97

- $26.05

$15.92

Oil cost per year

Heat pump cost per year

Savings per year

Continue this…

Do this for all temperature bins from 5 to

40 degrees F…

Total Savings

Over an average year in Maine, we

estimate that a 9000 Btu unit will save:

$444.05 per year

Suppose this…

If the furnace is 70% efficient:

$574.62 savings per year

Suppose this…

If the furnace is 70% efficient and oil costs

$4.00 per gallon:

$922.79 savings per year

Initial Cost

Equipment for a 9000 Btu unit is about

$1700 (varies depending on home)

Labor cost is about $900

Total ≈ $2600 initial cost

Tax Breaks + Rebates

30% Tax Break ($780 savings)

$250 Rebate from EfficiencyMaine

$75 Rebate from Bangor Hydro Electric

Total Savings = $1105

Net Cost

$2600 Initial cost

- $1105 Savings

$1495 Net Cost

Payback

Given a 70% efficient furnace at $3.00 per gallon

oil, the payback is:

yearsyearper

6.262.574$

1495$

Saving Versus Price of Oil (per gal)(70% Efficient Oil Furnace)

$226.44

$400.53

$574.62

$748.70

$922.79

$1,096.87

$1,270.96

$0.00

$200.00

$400.00

$600.00

$800.00

$1,000.00

$1,200.00

$1,400.00

$2.00 $2.50 $3.00 $3.50 $4.00 $4.50 $5.00

Price of Oil (per gal)

Savin

gs (

per

year)

Payback (years) Versus Price of Oil (per gal)(70% Efficient Oil Furnace)

6.6

3.7

2.6

2.0

1.61.4

1.2

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

$2.00 $2.50 $3.00 $3.50 $4.00 $4.50 $5.00

Price of Oil (per gal)

Payb

ack (

years

)

Afterwards

After unit pays itself off, you are saving

money every year.

Take a Loan

Taking a loan of $1500 at 8% interest paid over 5 years:

$30.41 per month

Compare to Heat Pump Savings:

$47.89 per month

Conclusion:

Heat Pump Pays for Itself + more

Save the Environment

Heating Fuel in Maine

Fact

Heat Pumps Produce Less CO2

then Burning Oil

CO2 Emissions

#2 heating oil emits 73.15 kg CO2per million BTU’s

The CO2 footprint of 1000 KWh in Maine is 1152 lbs.

Average footprint of US is 20 ton per person per year

http://www.eia.doe.gov/oiaf/1605/coefficients.html

CO2 Emissions for Oil

productionCOkg

lbs

Btu

kgBtuTotal2

1

2.2

000,000,1

15.73

1

CO2 Emissions for Heat Pump

productionCOKWh

lbsKWhTotal2

1000

1152

1

CO2 Savings

38.4% less CO2 produced

for same amount of heat

Or

~ 1 Ton less of CO2 per year

Conclusion

Other Alternatives

Residential Windmills:

~500 KWh per year in electricity

=

~$6.67 per month

Residential Windmills:

~$16,500 initial Cost

Heat Pumps

Heat Pumps:

~$47.89 per month

Heat Pumps:

~$2,600 initial Cost

Conclusion

Improve your existing heating system in

order to:

1) Save money

2) Save energy

3) Save the environment