Energy saving is one of key goals, related with installation of heat recovery in your buildings. Heat recovery contributes to reduction of energy use through different mechanisms, which are worth mentioning. I will present them, focusing on reducing heat escape from the building through ventilation and the savings associated with heat pumps and air conditioning.
How does heat recovery reduce heat escape in buildings through ventilation.
Traditional ventilation systems, which are equipped in heat recovery, often lead to significant loss of heat from the building. Ventilated air led out can have temperature similar to temperature inside, which leads to heat loss. Heat recovery systems enable heat recovery from this air and use it for heating or cooling of air entered into the building. Thanks to that, air escape through ventilation is significantly reduced, which translates into smaller need for energy for heating or cooling of the premises.
Does it make sense to use hoods in modern buildings with heat recovery?
Here we can talk about hoods, which you don’t use in modern buildings, however they still stay in the subconsciousness of Poles and they don’t want to let it go. Maybe because nobody wants to or maybe no one considered installation of heat recovery as saving energy use? I don’t know where this parochialism comes from and lack of thoughts on this topic among Polish and non-Polish plumbers. Let’s imagine a task like this, you take a glass bottle and try to take out all the air with your lips. Did you do it? This bottle symbolizes your home. Now we’re gonna do it the opposite way. Take a strainer and try to take out some air. Did you make it? Back in the day your homes were just like a strainer. Full of leakage, with “holes” in roof and windows, the hood had someplace to draw air from, but it’s not a problem because coal was cheap, nobody was bothered by those 1200m3 of air per hour in the house. Yours today buildings are unfortunately like the glass bottle, where the mouthpiece is heat recovery, which injects and extracts air. If we install a hood in this bottle, then which way is it going to draw air in to expel it to the outside? If through a heat recovery unit, running at 120m3/h, won’t it suddenly be hampered by a negative pressure and pulling 1200m3/h of air into the hood? You don’t have to be an eagle to agree that it does. In that case, what if I open the kitchen window? Again, this goes back to the unit, which you use to ventilate the house at 120 m3/h, so that the exchanger has the least possible loss, but also so that you don’t throw warm air outside, just to ventilate yourself with air that is a few degrees colder. In this situation you suddenly open a window in the kitchen and let 1200m3/h of air with temperature of -10’C in? How will it affect your savings? Isn’t it cheaper to eat in this expensive restaurant right around the corner? Last possibility is to connect the hood to the fifth spigot, which, bypassing the exchanger, will extract 400m3 of air from the cooker, but I don’t know if you know that an unit needs this heat in the exchanger in order to recover heat, so you will be extracting air from the cooker, throwing it outside, and blowing cold air into the house, because no manufacturer will agree to let greasy air from the cooker into their exchanger because it will destroy it. That’s not the way to do it and that’s not good.
In summary, in modern houses we don’t install hoods because in the winter it might be cheaper to eat in an exquisite restaurant than to prepare pork chop with potatoes for two…
What influence does heat recovery have on energy savings in the context of heating and air conditioning.
Heat recovery can significantly contribute to energy saving used for heating the building. In this article I mentioned about this many times, and here I highlight it. If we are supplying 100m3/h of air at +18‘C from outside, it is easier to heat it to 22’C than to -10’C from outside. So simple, yet so difficult for some. Savings coming from heat recovery in the context of heating the building are significant, they contribute to lowering bills for energy and long term finance savings. Heat recovery can also contribute to energy savings related to air conditioning in summer time. In climates where high temperatures occur, heat recovery can work in an opposite way, by forwarding chill from exhaust air to inside air. Thanks to that, air introduced to the building is naturally cooled, which reduces load on the air conditioner and limits use of energy needed to cool the building. Energy savings related with heat recovery and air conditioning contribute to reducing building exploitation costs and they are both beneficial for the environment and wallet. Conclusions of sing heat recovery in the context of savings come to mind by itself. It contributes to significant reduction of energy use in buildings. Limiting heat escape from the building through the ventilation and use of retrieved heat to heating or cooling the premises translates into energy savings. Additionally, heat recovery can cooperate with heat pumps and air conditioning, enabling further energy savings connected with these systems. Long term finance benefits related to lowering bills for energy, are an additional advantage of using heat recovery.
