Group 4 project on

1. Drain-Water Heat Recovery Why would you pay for heat only to let it go down the drain?

2. Whether washing clothes by hand or letting the machine do the work, the water going down the drain contains a lot of heat energy. For homeowners, this wasted heat energy costs several thousands kroner per year. For a business (school), it can add up to more than tens of thousands of kroner.

3. OUR PROPOSAL Toimplement “Drain-waterheatrecovery” in UncleTom’sCabin, usingthehotwaterusedbythewashing machines.

4. Howdoesitwork? Drain water flows through a spiral tube; this warms the tank water, which rises to the top. Water heater takes preheated water by circulation through a coil at the top of the tank.

5. Benefits Saves up to 40% on water heating costs!* Maintenance-free and has no moving parts to break down. Is environmentally friendly, reducing the energy consumption by five to 10%. Reduces greenhouse-gas emissions. * Heat-RecoveryWaterheatinghttp://gfxtechnology.com/HR3-7-1.PDF

6. Data Aftersampling 15 out of 200 studentstheresults show thatanaverage of 1.13 washes per personeachweekare done 200*1.13=226.6 washes per week. Thewashing machine takes 0.25 kWh per kilogramof clothes. Anaproximation of 5-7 kilograms are washedeach time 0.25*5=1.25 kWh 0.25*7=1.75 kWh

8. 402.5 kWh (0.50)= 201.25 krAssumingthatthe machines are used 9 monthseachyear: 5545kr 7765kr

9. Accordingtoinvestigationsthissystem can save up to 40% of thecosts. 5545kr saving 40% =2218kr. 7765kr saving 40% =3106kr.

12. ALTERNATIVE OPTION If for certain reasons the system can’t be applied in Uncle Tom’s Cabin, we recommend the College to use it in the new Leirskule building as a general system. It would be minimize the waste of energy through dissipated heat.