So, what is a microgrid, again?
Just doubled checked the most authoritative source, Google, and they define it as (a noun, of course), a small network of electricity users with a local source of supply that is usually attached to a centralized national grid but is able to function independently. Ok, now I remember. Now what if we apply this concept to a cooling “grid,” such as central chilled water distribution plant, and create a “cooling microgrid?”
Healthcare institutions are among critical facilities growing more aware and concerned with the impact and duration of short term electrical outages.
Many end users are currently addressing these concerns by further boosting stand-by power generation, increasing UPS (automatic power supply) storage capacity and providing CHP (combined heat and power) systems with black-start and islanding capability. But some operators are taking it a step further and boosting the resiliency of specific energy end-uses within their facility including cooling systems.
More and more hospitals are looking to incorporate independent and redundant cooling (mostly, chilled water) generating sources tied directly to emergency backup power systems to address critical cooling needs at the end-use level. An end-use based stand-by cooling system, which could supply one or a small, “micro” network of cooling end-uses, can provide needed redundancy without the complexity of segregating and controlling specific cooling loops among a wide and complex chilled water distribution network. An additional benefit of such a system, especially when piped and operating in series with a central cooling loop, is the ability to “super cool” supply air to a lower dew point, such as that demanded by critical spaces such as operating rooms. This can also allow the main cooling distribution network to operate at a higher chilled water temperature without having to satisfy the one or more, lower temperature applications, reducing central plant energy consumption and equipment wear.
So, here’s my new definition, if those Google execs (probably less than 30 years old) are listening, to add to our modern vocabulary: Cooling Microgrid (noun), a small network of cooling users with a local source of supply that is usually attached to a centralized chilled water distribution grid but is able to function independently.” I await my royalties.