The analysis performed shows that the production of condensate
from six large DOAHUs is sufficient to be effectively used for the
energy recovery process with 9.3% savings in case without heat pipe
and 10.9% savings using heat pipe strategy. The inherent recovery
of the totally free “cool energy” from the outside air to pre-cool the
incoming hot and humid outdoor air provides an attractive overall
energy efficient option.
Although HVAC energy use is often the primary focus, another
important part of sustainability is water conservation. It is shown
that water conservation strategy can be coupled with energy efficient
features to provide a better overall building design. In hot and
humid climates, the potential for generating substantial amounts
of water is available and should be pursued. With high quantities of
hot and humid outside air and 24 h per day operation, it is possible
to provide over 50% reduction in potable water necessary for cooling
tower make-up and to increase cooling tower efficiency due to
the introduction of a water source that has virtually no hardness
with a very low content of total dissolved solids.
This paper has a focus only on DOAHUs that require large quantities
of outdoor air on an ongoing basis.
Nevertheless, systems that are predominantly used usually
operate with both outdoor and recirculated air. Therefore, these
types of systems should be considered for implementing the proposed
system. In addition, regulations that require condensate to
be discharged into a sewer should be changed to allow for other
alternative uses. All commercial buildings using high capacity airconditioning
units should examine the feasibility of redirecting all
condensate drain water to a common point where it could be easily
captured. Other facilities that require strictly controlled indoor
air parameters like technology manufacturing or pharmacy storage
are convenient candidates for condensate recovery and should be
encouraged to install condensate capturing system.
Adopting the attitude that water is going to be the next “oil” like
commodity and understanding that the reuse potential for condensate
makes it much too valuable to simply be drained away is proper
approach that can help in managing a very precious and necessary
resource.