1. Heat Pump TEAM A: CAROLINE NAKANWAGI SUNGHEE MIN THERMODYNAMIC 2014 FALL

2. Overview  What is heat pump? :Thermodynamic principle  How does a heat pump work?  Advantages of heat pump  Energy types used in heat pump :Geothermal energy  Types of heat pump

3. THERMODYNAMIC PRINCIPLE  Use a volatile evaporating condensing fluid known as the refrigerant  Works by compressing the volatile liquid to make it hotter on the side to be warmed →the release of pressure to the side where heat isn’t being absorbed  The below diagram shows an example of a heat pump 1) condenser, 2) expansion valve, 3) evaporator, 4) compressor.

4. How a Heat a Pump Works The refrigerant when it’s in the gaseous state, it’s pressurized and then let to flow around the system by a compressor →This makes the vapor extremely hot and it’s cooled in the heat exchanger also known as the condenser →The refrigerant that has been condensed then passes through a metering device →This leads to a reduction in the pressure of the refrigerant →The low pressure refrigerant enters another heat exchanger →Here it absorbs heat and boils →The refrigerant then returns to the compressor and the cycle is repeated

5.  Generally the heat pump continuously cycles through the processes of Compression →Condensation → Expansion → Evaporation  The heat pump takes heat from the environment and channels it into a space or system which requires heating.

6. COMPRESSION, CONDENSATION,EXPANSION AND EVAPORATION  Inside the chambers of the heat pump is allowed to expand in a continuous process :when the gas travels through the expansion valve, the gas absorbs heat in the form of stored energy from the air, water or the ground  As the cycle continues, the gas is compressed and it releases the energy in the form of heat  The performance of heat pump is measured by the C.O.P.( Coefficient of Performance) :the ratio of the heat pumped into the hot reservoir to the work input to the heat pump  Heat Pumps aren’t 100% efficient 1 st Therm. Law: energy can be changed from one form to another but can’t be created or destroyed 2nd Therm. Law: work can be converted to heat but the process isn’t 100% efficient

7.  If the heat pump is doing reversible work, then the Carnot cycle is traversed in the opposite direction  The signs of w and q in the individual segments and the signs of w and q in the overall process are changed  Heat is now withdrawn from the cold reservoir that is the surroundings and deposited into the home, which is the hot reservoir  Since this process isn’t spontaneous, work must be done on the system to effect this direction of heat flow  Heat pumps become less effective as the temperature of the cold air decreases.  Therefore, geothermal heat pumps are better

8.  Advantages of Heat Pumps Saving energy and money Protecting environment No need of any maintenance  Environmental energy can be from Ambient Air Water Brine (Ground heat)

9.  What is Geothermal Energy? Geo (Greek for Earth) Thermal (heat) Temperature of Shallow Crust from 55-75 F(Upper 10 ft.) to 14,400 (Molten Core -4000 meter to center of core)

10.  Brief History of Geothermal Energy Paleo0Indians Usage Dates 10,000 years ago Use by Romans- Hot Spas; Hot Running Water Early 1800s – Yellowstone hot Spring and Hot Spring Arkansas 1830 1st Commercial Use; Asa Thompson

11.  Geothermal Potentials Seasonal variations measurable until 10-15 depth At 10 meters depth the ground is approximately 1K warmer than the yearly than the yearly average ambient temperature In high depth the temperature rises 2.5-4K each 100meter For passive cooling depths of 30-100 meters are suitable bath in Wooden Tub for $1

12.  Brine Source Heat Pump  Air Source Heat Pump  Water Source Heat Pump

13. A. Brine Source Heat Pump : ground heat as the heat source Horizontal Collector Vertical Collector

14. B. Air Source Heat Pump: air as the heat source-air /water heat pump External Installation Internal Installation

15. Air Flow in Heat pump

16. A sectional drawing

17. C. Water Source Heat Pump: ground water as the heat source–water/water heat pump