Attic Heat Harvester
The Attic Heat Harvester Ltd. powerful microprocessor based Differential Temperature Controller is designed for applications
that compare two thermistor derived temperatures to control external devices based on user pre-settable parameters and a
predefined algorithm. The Differential Temperature Controller also calculates, displays and remembers system performance data.
In the Attic Heat Harvester guise the Differential Temperature Controller continually monitors an attic and a room sensor to determine whether a fan should be turned on to move solar heated attic air from the attic to one or more rooms.
Hardware
System input power: 230vac 50Hz (default) or 115vac 60Hz. - voltage selection made using links.
Micro Processor: Microchip PIC16F1936
Clock rate 2 Mhz
Controller power consumption excluding relay output power - 1 Watt
| Thermister: Inputs: |
1 - Attic thermistor 2 - Room thermistor |
30K at 25C 30K at 25C |
| Outputs: Display: Keypad: |
1 - 3 amp 230vac SPNO relay - provides 230vac (115vac) to power fan 2 - 0.05 amp max, 18-26vac SPCO relay - provides 24vac to open/close main air valve Option: 3 - 1 amp 230vac SPNO relay - provides 230vac (115vac) to power attic cooling fan 2 line x 8 character 5.6 mm high LCD display with LED backlight 3 push buttons: 'MODE', '+', '-', |
|
Indicators: |
1 - +5vdc on - 2 - System running - 3 - Fan On - |
Green LED Yellow LED - flashes each second in normal operation flashes differently if system errors detected - see error codes Red LED |
Enclosure: |
110 x 110 x 68mm (4.35 x 4.35 x 2.7 in) with clear polycarbonate lid Fixing holes: 4 in a rectangle spaced at 95mm (3.75 in) Weight 0.5kg (1.1lbs) |
|
| Temperatures Current Power (cPwr) Current Efficiency (cEff) Total Power (tPwr) Total Efficiency (tEff) Fan Hours (FHr) Average Temperature Difference (AvTD) |
-9.9 to 70°C in 0.1°C increments 18 to 160°F in 0.2°F increments 0 to 65.5kW in 0.1kW increments 0 to 99.9 in 0.1 increments 100 to 999 in increments of 1 0 to 999.9 kWhrs in 0.1 kWhr increments 1000 to 16609 kWhrs in increments of 1 0 to 999.9 in 0.1 increments 0 to 999.9 in 0.1 hr increments 1000 to 6553 (270 days) in 1 hr increments 0 to 25.5°C or 0 to 45°F |
| Range | Default | |
| Attic Temp - Room Temp (AtT-RmT) Max Room Temp (MaxRoomT) Fan Flow (Fan-Flow) Fan Power (FanPower) Max Attic Temp (MaxAticT) |
0 to 25.4°C 0 to 42°F 5 to 30°C 41 to 86°F 0 to 5120 cmh 0 to 3060 cfm 0 to 255 watts 35 to 60.7°C 95 to 141°F |
3°C 5.4°F 23°C 73.4°F 1400 cmh 820 cfm 90 watts 50°C 122°F |