Enhancing a Ground Source Heat Pump with Supplemental Energy - - PowerPoint PPT Presentation

Enhancing a Ground Source Heat Pump with Supplemental Energy

THERMAL ENERGY SOLUTIONS

Agenda

Introduction Current home heating energy consumption Constraints Ground-source heat pumps System layout Supplemental energy sources

• Grey water
• Solar collectors

Additional cost savings Conclusion

Introduction

Four fifths of average Canadian energy use can be attributed to heating (both space and water). Existing heat pump technology significantly reduces home heating energy consumption. Our task is to improve home heating energy efficiency through enhancing the performance of a heat pump.

2% 4% 14% 17% 63%

Energy Consumption

Space Cooling Lighting Appliances Water Heating Space Heating

Current Home Heating Energy Consumption

Based on residential heating in Atlantic Canada

• Energy required for space heating: 24,750 kWh
• Energy required for water heating: 5,650 kWh

Three conventional heating methods

• Combustion:

COP = 0.97

• Electricity:

COP = 1.00

• Heat Pumps:

COP = 4.00

Cost of heating

• Electric Heat: $3,586
• Heat Pump: $982

Constraints

Economic

• Heat pumps are already highly efficient
• Any improvements must be

economically viable, with a reasonable

• verall system payback period

Environmental

• Overall carbon footprint must be

reduced

• It does not make sense to shift the

problem from one place to another

Ground Source Heat Pumps

Operating principles

• Based on the Carnot Cycle, which

utilizes a power input to create a temperature difference between two thermal reservoirs.

• Energy is drawn from the ground,

and passed into the home using a refrigerant. 𝐷𝑃𝑄𝑁𝐵𝑌 = 𝑈𝐼 𝑈𝐼 − 𝑈𝐷

System Layout

Supplemental Energy Sources

Any supplemental energy source had to meet key criteria:

• Low up front cost, to ensure a reasonable pay back period
• Minimal inconvenience to the home owner

Based on these criteria, two potential sources were selected for further study:

• Grey water
• Solar thermal

Supplemental Energy Sources

Grey Water

5% 10% 20% 30% 35%

Water Usage

Cleaning Kitchen Laundry Toilet Flushing Bathing

Water consumption facts:

• Average Canadian consumes

343 L of water per day.

• For a 4 person household, that

amounts to 1372 L.

• 480 L of this is hot water, which

would be recoverable for energy harvesting.

Supplemental Energy Sources

Grey Water

5% 10% 20% 30% 35%

Water Usage

Cleaning Kitchen Laundry Toilet Flushing Bathing

How the system would work:

• Grey water would be collected

in an insulated storage tank.

• It would then be used to boost

the temperature of the heat pump ground loop.

Energy potential:

• 480 L of grey water, at 40 °C, can

impart 60,000 kJ of energy to the heat pump ground loop.

• This would result in an average

performance increase of 1.31%.

Supplemental Energy Sources

Solar Thermal

Solar thermal facts:

• The amount of recoverable solar

energy varies widely by location within Canada.

• In Atlantic Canada, the

insolation is relatively low, while in the Prairies, it is quite high (comparable to Sydney, Australia).

Supplemental Energy Sources

Solar Thermal - GHSP

How the system would work:

• The heat pump glycol loop would be

redirected through the solar thermal collector.

• A 12 m2 solar collector was selected.

Energy potential:

• This would result in an average

performance increase of 1.1% in Atlantic Canada.

• This would result in an average

performance increase of 1.64% in the Prairies.

Supplemental Energy Sources

Solar Thermal - Hot Water Heating

How the system would work:

• Water would be pumped through the solar

collector, heated, and then stored in an insulated tank.

• Two 2.5 m2 collectors would be required for

the average Canadian home.

Energy potential:

• Atlantic Canada
• 94% in the summer
• 47% in the winter
• Prairies
• 100% in the summer
• 76% in the winter

Additional Cost Savings

SYSTEM ADDITIONAL ENERGY SAVINGS (kWh) ADDITIONAL COST SAVINGS

ENHANCING A GSHP GREYWATER 130 $13 SOLAR THERMAL - ATLANTIC CANADA 400 $40 SOLAR THERMAL - PRAIRIES 540 $92 STAND-ALONE GSHP AND SOLAR THERMAL WATER HEATING ATLANTIC CANADA 3200 $320 PRAIRIES 4720 $802

Conclusion

We set out to reduce household energy costs by implementing an enhanced ground-source heat pump. There is one major problem with this:

• Heat pumps are too efficient

It would be more efficient to use a GSHP to supply heat for space heating and use a solar collector system to preheat water for hot water use.

Thank you! Any questions?