| Traditional Residential Direct Evaporative Cooling | |
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| Mechanical Cooling | |
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| IDEC Cooling | |
Inexpensive Mechanical Cooling |
Direct Evap |
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| ASHRAE bin hours ~2% 85 DB / 30%+ RH | |
| Inexpensive Mechanical Cooling |
Smaller Mechanical Equipment |
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IDEC Systems are able to run a large 3+ story building on fans, cooling tower, indirect water pumps and evap pumps for 98% of cooling season supplemented by less expensive 1st cost and operating cost chiller.
Example HAFB
From this type of system the end result is a typical payback of 3 years on 30,000 cfm and above airhandlers.
Stages of IDEC
1. Economizer
2. Economizer + Indirect Cooling Coil
3. 100% OSA + Indirect Cooling Coil + Direct Evap (Stage ICC Coil not Direct Evap for control)
4. Mechanical Cooling + Indirect Cooling Coil
Design considerations.
- Once you go to stage 4 stay on stage 4 for the day to avoid nuisance changeovers.
- Turning on and off evap pump can shorten pad life and burnout pump. Use bypass damper on stage 3 if temperature drops below setpoint with ICC coil turned down. If bypass damper is open for extended period of time then turn off evap pump.
- Dump evap sump nightly or every 3 days to eliminate growth on pads and sump.
- Amount of water usage for evap cooling is significantly less than amount of water used to power turbines etc for mechanical cooling of traditional system.
- Auto flush and fill system will eliminate reasonable chance of legionella disease.
- Media holds water like a sponge, typical 20,000 cfm unit uses 2.5″ overflow drain, 50,000 cfm unit uses 3″ overflow drain, 75,000 cfm unit uses 4″ overflow drain.
New media must be flushed and dumped about 6 times before resin is cleaned enough to minimize water carryover.