Lecture 13Geothermal Energy and Heat Pumps

E-101 - Energy and Sustainability Professor Lonnie Gamble

Sustainable Living Department Maharishi University of Management

This presentation was prepared on solar powered computers

Low Temperature Geothermal – using the steady temperature a few meters deep in the ground or body of water (usually around 55 degrees) for heating and cooling. Usually requires a heat pump.

High Temperature Geothermal – using the high temperature deep in the earth to make steam and generate electricity. In special places, like near volcanoes and hot springs, high temperature heat can be close to the surface.

Low Temperature Geothermal(Product Promotion Video)

Heat Pump Coefficient of Performance (COP)

Heating mode:COPheating = Energy Delivered/Energy RequiredTheoretical Maximum: Th/(Th-Tc)

Peak COP can be as high as 5 -6 Seasonal COP usually 2-3With building temp at 70, as low temp approaches 30 , COP =1.

Cooling mode (refrigerators or air conditioners):COPcooling= Th/(Th-Tc) Typically 2-4

CondensorEvaporator

Condensor

Evaporator

High Temperature Geothermal

Google Deep Geothermal

Heat Pump Coefficient of Performance (COP)

Heating mode:COPheating = Energy Delivered/Energy RequiredTheoretical Maximum: Th/(Th-Tc)

Peak COP can be as high as 5 -6 Seasonal COP usually 2-3With building temp at 70, as low temp approaches 30 , COP =1.

Cooling mode (refrigerators or air conditioners):COPcooling= Th/(Th-Tc) Typically 2-4

Seasonal Energy Efficiency RatioSEER

SEER = [Total Cooling Output Over the Cooling Season] / [Total Electrical Energy Input Over the Cooling Season]

SEER= BTU/watt-hrAfter 2005, must be greater than 13Energy Star = 14Highest Commercial Units = 20Window Units = 10 or less

Solar

https://www.youtube.com/watch?v=cz-kquRmvqkair conditioning

Swamp Coolers

https://www.youtube.com/watch?v=6ooAAcsbf_0

Heat Pump https://www.youtube.com/watch?

v=KH47xAXEEe0

Coefficient of PerformanceMaximum Theoretical Heat Transfer

Heat PumpCOPHeating = Th/(Th-Tc)

Ex: Th = 75 deg F = 75 + 460 = 535 deg R Tc= 55 deg F = 55 + 460 = 515 deg R

COP = 535/(535-515) = 26.75

Air Conditioner/ FridgeCOPCooling= Tc/(Th-Tc)

COP Cooling = COPHeating – 1

All temp in absolute scale R= F+ 460

Note: All T in absolute temp, Rankine RDeg = Fdeg+ 460