Special Maintenance Considerations - Effective Building Maintenance: Protection of Capital Assets - page 102

gated they are water “hogs.” First, replace as much lawn area as
possible with “natural” areas or areas landscaped with drought-re-
sistant plants. Next, for those lawns that must remain, select grasses
that require little or no watering beyond natural rainfall. (The typi-
cal high cost of maintenance for lawns should automatically make
them a target for reduction!)

The recovery and recycling of wasted water to offset irrigation wa-
ter consumption is also an option, as follows:

• Normal operation of cooling coils produces condensate water that

typically drains to the sewer. But, condensate is clean water that can
be captured and reused for non-potable water applications. Typical
applications include cooling tower make-up, flushing fixtures, and
landscape irrigation.

Considerations for condensate recovery systems include:
— Condensate recovery works by gravity flow. A drainage system
from each air handling unit to a central connection point, a hold-
ing tank or cistern, is required. A pump then supplies make-up
water from the holding tank or cistern to the cooling towers.
— Collected condensate water is at temperatures between 50 and
60°F.
— To use condensate as cooling tower make-up , a 3-way valve in
the line feeding make-up water to the cooling towers is required
to allow the system to draw from reclaimed condensate or ser-
vice water as needed for level control. Normally, the cooling
towers need more make-up water than can be recovered from
the condensate, in which case the system uses supplemental do-
mestic water.

The amount of condensate produced by cooling will range from
0.005 to 0.0167 gpm/ton, based on the amount of outdoor air and
the climatic conditions that exist. Thus, a 100 ton commercial HVAC
system, operating for 2000 equivalent full load hours annually, can
produce as much as 70,000 gallons of clean condensate that can be
captured and used in lieu of potable water sources.

One caveat regarding cooling condensate recovery: during cool-
ing coil cleaning operations, all water from the drain pan must be
drained to the sanitary sewer. This may require bypass piping to