Evaporative cooling and humidification
High-pressure water atomized, reduces cooling load and energy costs by Dave Schwaller, Mechanical Engineer
DriSteem Corporation, Eden Prairie, MN
Evaporative high-pressure systems are used to cool and humidify air for processes, products, preservation, and comfort. These flexible systems can be installed in airstreams or directly in the space to be conditioned.
They use very little electrical energy to operate and can be located long distances from the air being conditioned. A single system can condition multiple zones and cool supply air directly and/or indirectly through a heat exchanger.
The following characteristics are typical of evaporative high-pressure systems:
Reduced cooling load: The evaporative cooling effect can draw enough heat from the air to produce a 20 °F or more temperature drop. One pound of water evaporated into the air removes approximately 1000
Btu of heat; 12 pounds of water
Twelve pounds of water equals about a ton of cooling.
Energy savings: Evaporative high-pressure systems require very little energy to deliver water droplets into the air about one percent of the energy used by an electric humidifier per pound of water.
evaporated into the air equals about a ton of cooling.
Evaporative high-pressure systems provide significant energy savings compared to other evaporative technologies.
Minimal maintenance: Systems using reverse-osmosis (RO) or deionized (DI) water require very little maintenance, particularly if the pump and atomizing nozzles are low- or no-maintenance stainless steel.
Pure, particulate-free cooling and humidification: When using RO or
DI water, systems with high-grade stainless steel parts can disperse atomized water particles without dispersing bacteria, viruses, or minerals.
High capacity: In air handlers and ducts, capacity is limited only by duct or air handler size and evaporation capability. In open spaces,
very large capacities can be met with a single system or with multiple smaller systems.
Evaporative cooling and humidification psychrometrics
Table 2-1 presents how an evaporative high-pressure system can be configured for regional outside conditions and reconfigured for seasonal changes. Operating conditions for each scenario are charted in Figure 3-1.
Table 2-1: Seasonal/regional scenarios and evaporative high-pressure system design factors
