The typical HVAC system serves to keep occupants of the structure comfortable, or, as we have learned in our ongoing series of special HVAC uses, it can provide the ideal environment for growth and production. However, we haven’t considered the instances where a proper HVAC system means the difference between life and death. In the next two blogs we will look at two situations where the HVAC system makes surviving the elements possible.
Private space travel has made a trip to the stars a reality for everyone. Anyone that can afford it, that is. While it is filled with planets, and incomparable views of our planet and the universe, it is also a very inhospitable place. NASA states that the International Space Station is as hot as an oven on its sunny side at 250°F and a frigid -250°F on its dark side.
With extremes like that, it takes a special and intelligently designed system to keep all the components and people inside safe and working properly. In addition to the temperature extremes, two other factors had to be considered. In a microgravity environment, hot air doesn’t rise, and cold air doesn’t sink; they both diffuse. Likewise, gain and loss of heat is only through radiation; there is no convection or conduction.
As is in most cases, the place to start is insulation. The station is basically almost entirely wrapped with a reflective coating that keeps the sunlight from radiating heat onto the station, and the shady spots from radiating heat out.
Inside the station, the excess heat generated by both the people and the machinery is controlled through a dual-exchange heat system that mechanically pumps fluids in closed-loop circuits to collect, transport, and reject heat. A water-based loop propelled by a rotor run from the inside and through an ammonia-based heat exchange system.
The ammonia keeps the water from freezing once it leaves the climate-controlled interior. The heated ammonia enters honeycomb-panel radiators located on the outside of the station in the shade. The heat is released into space and the process keeps flowing.
Though the process used in space is more complex, the process of using fluid loops for heat exchange is the basis for how geothermal heat pumps work. It is amazing that the complexity of maintaining livable conditions in space has its roots in harnessing the naturally occurring power below the surface of the earth.
So the next time you are enjoying the comfort of home with your family, take a moment to appreciate the simplicity and readily available support from Quigley for your HVCA system. And be sure to take care of it with regular maintenance so it can continue to provide you with comfort in all temperatures.