Heat Pump Clothes Dryer

Presented on April 23, 2008

By

Brian PollicaMichael Hildenbrand

Product Background

The clothes dryer is one of the most common appliances in a typical household. A typical family of 3 can do an average of 6 loads in the dryer in a typical week. The energy put into a dryer is not completely utilized by the dryer, thereby exhausting a certain amount of energy to the atmosphere. If the energy can be calculated and captured, the energy savings to the home owner may be significant.

Design Considerations

Capture the heat exhausted to do one of the following:

Condition the air to heat a building Utilize a heat exchanger to:

Preheat water to reduce hot water heater costs, or

Preheat the inlet air to reduce energy usage by the dryer

Utilize a heat pump to re-circulate the exhaust air

Calculations Air Conditioner

SEER = BTU / W*HCOP = SEER / 3.792

Peak Wind Speed 18.6 knots 1883.6 fpm

Peak Temperature 118.6 ºF

Exhaust Diameter 4 inches 0.333333 feet

Exhaust Area 50.27 in² 0.349066 ft²

Air flow 657.5004 cfm

Calculation based on minute Δt

Volume 657.5 ft³

18618.33 liter

Pressure 1 atm

Temperature 118.6 ºF 70 ºF

48.11111 ºC 21.11111 ºC

321.2611 K 294.2611 K

Ideal Gas Constant, R 0.082058 L*atm*K-1*mol-1

amount of substance, n 706.2565 mol

Heat Capacity of Water, Cp 29.07 J*K-1*mol-1

Energy exhausted to air 554333.7 J 525.7 BTU

132488.9 Cal

SolutionHeat Pump Clothes Dryer

Re-circulation of exhaust air Temperature and Humidity sensors Condensation control Interface with Dryer

controls for shut offs and heat control

CondenserCoils

Evaporator Coils

Dryer & Heating Element

Compressor

ExpansionValve

DAQ

Temperature sensor

Humidity sensor

Temperature sensor

Humidity sensor

Heat Pump

System Overview

Front panel

Back Panel

Temperature Sensor Circuit

LM335

The voltage out is 3V which is obtained using the voltage divider circuit created by the 1K resistor and the LM335. The LM335 operates at the 3V level and will change the output voltage by a few hundred mV depending on the surrounding temperature, as the temperature goes up the output voltage will go up and vise versa as temperature goes down.

Humidity Sensor Circuit

Organization (Planning)Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12 Week 13 Week 14 Week 15

Organization

Solution Development              

Develop Presentation

Presentation 1    

Presentation 2    

Presentation 3  

Develop Web Content                

Final Presentation        

Testing

Test AC unit    

Test Dryer Unit    

Revise System Requirements    

Design

Electrical Circuits          

Mechanical System          

Build

Heat Pump system        

Exhaust/Intake Loop        

Install Electrical/Sensors        

Assemble Final System        

Software

Develop system requirements      

Develop programming            

Michael   Mechanical, Presentation, and Management

Brian   Electrical, Software, and Web content

Both  

Budget

Description Project Cost ActualAC Unit Donated $449.99Dryer Unit Donated $251.10Temp Sensors Donated $1.56 - $7.35Humidity Sensor

$7.92 each (2) $7.92 each (2)

Lab View Available $2499Polycarbonate Donated unavailable

Total $49.76 $3237.13

Duct work and hardware – 18.69Appliance cord – 8.47

Summary/ConclusionsThe heat pump is much too low for this application.