Energy Services Bulletin banner

Thermodynamic discovery increases energy efficiency

In conventional indirect evaporative cooling, the working air stream passes through the wet channels of the heat exchanger only once. This cooler air draws the heat from the product stream passing through the dry channels. (Artwork by Idalex)

Dr. Valeriy Maisotsenko, former director of the Thermal Physics Research Laboratory in Odessa, Ukraine, brought a new thermodynamic cycle with him when he came to the United States in 1992. 

Humidity affects different air temperatures
To understand the Maisotsenko Cycle, or M-Cycle, it is first necessary to explain the thermodynamic concepts of dry bulb temperature, wet bulb temperature and dew point. The dry bulb temperature is the air temperature measured with a standard thermometer.

A standard thermometer with a wet piece of cloth covering its bulb is used to measure wet bulb temperature. As air passes over the wet cloth, the water in the cloth evaporates, drawing heat out of the thermometer. The wet bulb temperature is therefore lower than the dry bulb temperature.

Taken together, the dry and wet bulb temperatures are used to calculate the moisture or humidity in the air. The greater the difference between the two temperatures, the drier the air is.

The dew point is the air temperature where moisture in the air begins to condense or change from a vapor to a liquid. For dew to collect on a surface like a glass of ice water or blade of grass, the surface temperature must be at or below the dew point temperature. The dew point temperature is always the coldest of the three temperatures.

Heat exchanger key to cycle
Theoretically, the wet bulb temperature is the lowest temperature any evaporative cooling system or cooling tower can achieve. However, the M-Cycle is able to use indirect evaporative cooling technology to cool well below the wet bulb temperature, almost to the dew point of the incoming air.

In the Maisotsenko Cycle, both the product and working air are incrementally cooled by some of the working air that is fractioned off to absorb moisture and heat. Because the working stream gets colder as it progresses through the cycle, it is able to draw more heat out of the product stream. (Artwork by Idalex)

This is accomplished with a wet- and dry-channel heat and mass exchanger that is geometrically very different from a conventional IDEC component. The uniquely designed plate-wetting and channel system splits the incoming air stream into product and working (exhaust) streams. 

The working stream is first pre-cooled in a dry channel, then split again into many streams and directed into wet channels. The wet channels cool and saturate the working air incrementally, with each stream benefiting from the cooling on the next increment. This cycle occurs multiple times in a short physical space within the exchanger, resulting in progressively colder temperatures.

The product stream travels the entire length of the exchanger in dry channels. Heat from the product air transfers across a heat exchange plate and into the colder working air and water as it evaporates on the working, wet side of the plate. The heat and moisture are then rejected as exhaust. When it enters the space to be conditioned, the product air has been cooled below the wet bulb of the incoming air with no moisture added.

M-Cycle has many applications
This new thermodynamic cycle, once considered impossible by scientists, promises tremendous energy-efficiency gains in HVAC, water-cooling and power production. T he Maisotsenko Cycle is the foundation of the Coolerado cooler. In independent laboratory tests, a cooler cooled product air up to 22 percent below the wet bulb temperature, and to within 85 percent of the dew point temperature.

Idalex, the company that patented the M-Cycle, is currently working on other applications for this thermodynamic breakthrough. A Maisotsenko combustion turbine is in the design phase and Idalex is testing the first prototype of a highly efficient refrigerant condenser using Maisotsenko technology.