Why not recycle the heat with air conditioning?Another way to do this is with variable refrigerant flow (VRF) heat pumps. These are the big brothers to minisplits that allow you to do simultaneous heating and cooling, bypassing the outdoor unit of the heat pump altogether. The refrigerant picks up heat in a room that needs to be cooled and sends it to another room that needs to be heated.Using waste heat from computers reminds me of Martin Holladay’s April Fool’s Day article a few years ago: Researchers Predict U.S. Furnace Industry Is Doomed. In it he wrote that plasma TVs would soon be labeled with their heat output in BTU/hr. Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. Check out his in-depth course, Mastering Building Science at Heatspring Learning Institute, and follow him on Twitter at @EnergyVanguard. Put a “data furnace” in your basementIt’s not a new idea. As long as people have been going into server rooms and feeling the heat, they’ve been talking about what a great idea it would be if you could use that heat. It’s fairly low-grade heat, though, so it wouldn’t be ideal for generating electricity, but is just right for heating buildings… if you can get the heat to where it needs to be. The Amazon plans aren’t out yet, at least not in what I’ve seen, but they’re going to capture the heat in water and move it to their office building.A few years ago, Microsoft published a paper called The Data Furnace: Heating Up with Cloud Computing, which looked at the possibility of heating homes with servers. They found that it would take 37 to 114 of those 350-watt servers to provide all the heat for homes in five different climates. The owner of the data furnace would net about $300 in savings for each server.It’s an interesting idea, but I just don’t see that one taking root. What Amazon is doing, though, should represent a new trend. And Seattle is the ideal place to do it because their design temperatures are moderate and they use heat throughout the year. I recall having the heat on and wearing my wool sweater even in July one year when I lived there. RELATED ARTICLES Capturing and Distributing Waste Heat From Power GenerationDistrict HeatingCombined Heat and Power in SwedenBringing Combined Heat and Power to BrattleboroResearchers Predict U.S. Furnace Industry Is DoomedWater Heat Exchangers Last week in my ASHRAE newsletter, I saw an interesting story about a cool thing that Amazon.com is planning to do with heat. Amazon, in case you didn’t know, is a heavy user of computers. Not only do their run their online store but they also have a popular cloud computing service. Computers turn electricity into kitten videos, celebrity tweets, and waste heat. And despite what Facebook and Twitter may have led you to believe, that last one is the most important.A typical server uses about 350 watts of power and produces about 1,200 BTU/hr of waste heat. (These numbers are from a paper written in 2011, but more about that later.) With 50 servers, you could get as much heat as a 60,000 BTU/hr furnace, but most of the time that heat is not only not used, the owner of the server farm pays to have it removed from the server room with the use of air conditioning — even in cold climates. Amazon is building a new office center in Seattle, and they’re planning to heat it with waste heat from a nearby server farm. The project is going through the approval process with the local government now, but this would turn around the energy flows and make use of the heat given off instead of using more energy to get rid of it.