By insulating an apartment building it is possible to reduce heat consumption by 40%. However, after implementing recovery, the cost may only drop to a third of the original cost.
As energy prices rise, people are forced to conserve it. And it’s not just about electricity. A typical family spends most of its money on heating and water heating. The problem is that we waste a lot of this heat. And it’s not just about needlessly impacting the premises.
- What’s behind the idea of heat recovery from wastewater and stale air.
- What parts does the system consist of and what are its space requirements.
- Do you have to worry about smells, noise and how to deal with power outages?
- Where the technology is already used and what savings it has brought to the population.
- How much does the system cost and what is the payback period.
Legislation pressed them
What led you to develop a recovery system for condominiums?
We initially used heat pumps to heat hot water. We had a patent-protected solution. With a relatively small heat pump we were able to supply hot water to the entire apartment building. Since this represents around 50% of heating costs, it has proven to be a very effective, simple and economical solution with rapid payback.
But when, due to the change in the Law on Thermal Energy, one, second, third construction procedure was not approved, we had to look for new solutions.
And that’s why we invented that we capture the heat just from the object and give it back. And here we have in our hands a strong constitutional law for the protection of personal property. Simply put, the heat that I have already purchased or once placed in my home is my personal property. And when I pick it up and bring it home, I’m simply working with my personal possessions.
Ján Šmelík graduated from the Faculty of Civil Engineering of the then Slovak Technical University in Bratislava. Initially he worked as a designer in various companies and since 2005 he has worked as a freelancer. He has designed numerous boiler rooms, heat transfer stations or machine rooms with heat pumps, mainly in non-standard solutions in various combinations of individual heat sources.
In 2013, together with his partner Peter Štefanec, he founded the company Energia Real, in which they are dedicated to the development, production and operation of technologies for special heat pump applications. In 2020 they received the award of the Minister of Economy of the Slovak Republic in the Innovative Act of the Year competition for 1st place in the technological innovation category.
So you developed the recovery technology also because the legislation pushed you to do so.
Legislation is a problem from several points of view. So, for example, no other heat source can be built within the reach of the central heat supplier without its consent. So, thanks to this, the construction of boilers has stopped, which on the one hand is good, because breaking the central source and then making gas boilers with their own chimney that smokes in each house is not quite the right solution.
But all this was done in such a monopolistic way that no heat source existed. But this does not mean a solar collector or a heat pump. And it was really followed and almost nothing was built in 10 years starting from 2012. And this situation actually pushed us into developing this technology.
“We are convinced that this system can be installed anywhere. We are always trying to invent something. At least technically.”
The existing room can be used
What parts is your system made up of and what does the condominium need to provide or purchase for it to work?
The condominium does not have to provide anything directly. We try to provide technology as a complete package, both materials and services. Part of the air recovery technology is placed on the roof. It looks similar to regular air handling units found on the roofs of houses. It is also a set of tanks, exchangers, valves, pipes and one or more heat pumps.
What space requirements does this technology have?
The technology normally occupies a room, approximately 3×4 metres. Furthermore, we still need a wastewater tank, which we do on the lowest floor, where we cool the wastewater in a controlled manner and discharge it into the sewer system.
This means that a condominium can use, for example, a former laundry room for these purposes. However, such rooms within the common spaces are not a matter of course. What if the condominium simply does not have such space?
Now in the planning phase we are fighting with an object in Košice, which literally has no space, so it will probably be about deepening a technical space underground or making some small expansion under the loggia of the first floor above ground.
So unfortunately yes, in renovations taking care of space is probably the greatest art. Well, we are convinced that this system can be installed anywhere. We’re always trying to invent something. At least technically.
However, many times the condominium does not have its own land around it. They belong to the city, which is therefore a complication in construction proceedings, zoning proceedings and so on. So the solution would be simpler if the construction process was simplified and we could quickly obtain a building permit, for example, for a well near the building. So we can do it in a completely ordinary way with some prefabricated wells and putting the technology directly into them.
Photo gallery
The room where most of the technology necessary for the system described is located. Source: Ján Šmelík
What is installed in the houses themselves, that is, in apartments?
The system does not require entry into the apartments. We move only on the lowest floor and on the roof of the building. For a standard house of this type, let’s say with 50 apartments, you have to sacrifice around 20 m2. With the growing number of apartments, the needs in this area are not increasing much. Only a slightly larger tank, a compressor and so on will be used. The requirements are more or less the same for a small or large object.
How to imagine a tank in which wastewater is concentrated?
In fact it is something like a cesspool. It has dimensions of only 2 × 3 m and a height of 2 m, i.e. 12 m3. It’s hidden behind a standard plaster wall, so you don’t even know it’s there.
Such a solution is necessary. Especially in Germany there have already been some experiments in which they cooled the sewage system in such a way as to insert the exchangers directly into the pipes and then feed them. However, they didn’t know how to properly cool the wastewater. I have never come across controlled cooling of wastewater at the level we have achieved anywhere in the world.
Don’t have to worry about the smell?
It’s an airtight space, so odors don’t spread from there.
“If there is a fire, the system will detect it directly in the ventilation. Any fire is therefore detected almost immediately, so the fire brigade can intervene on site a few minutes earlier.”
Seconds like a fire alarm
Isn’t your system noisy?
Now we are delivering a house in Sliač, but it is a very large building. It has six entrances, it is a low and long “silt”, so we solved the air recovery there only, in a relatively simple way. And there we encountered a problem: they didn’t have a common space. The gas boiler room was already there, we just added it. In the space between the stair landings we therefore installed heat pumps with a power of 200 kW. At the same time, it is a technology that makes big money.
We knew in advance that reducing the heat pump, which has 80 decibels, during sleep to a value of 30 decibels is almost impossible. Well, in front of the engine room door we actually managed to reach 33 decibels. In apartments, even with all coefficients, it is most pronounced below 30 decibels. But, of course, we have come across a family where no and no… the owner still feels it.
So in every house there is some rebel who brings with him more, which is why he cannot be put into operation. At the same time, people save a lot of money there. But each of these implementations represents a new challenge and moves us forward. If we had not experimented with such diggers, no one would have forced us to reach the limits of 20 decibels, which is practically inaudible to the human ear.
Can’t your air recovery somehow change the pressure in the apartment building? Can the system adapt when more windows are opened, etc.? Is there controlled ventilation?
Ventilation is controlled and, thanks to the pressure sensor, the roof fan automatically varies its performance as conditions change. Furthermore, there is also a CO2 sensor, based on which we can see the intensity of the ventilation. There are also fire sensors that increase the safety of the building. If there is a fire, the system will detect it directly in the ventilation. Any fire is therefore detected almost immediately, so firefighters can arrive on site a few minutes earlier.
On the other hand, can your system cool down when it’s hot?
Cooling is a bigger problem, because in apartment buildings we don’t have many options to transfer the cold into the environment. By default, this is not possible with radiators, and adding ceiling, wall or floor cooling to apartments is financially demanding and requires access to each individual apartment.
Well, once I have the heat pump, I can also use it for cooling in the summer. So far no one has expressed interest, but we offer a solution such that a cooling water riser is built in the stair space or central corridor. Anyone can connect to it via a cold consumption meter and can install, for example, a fan coil (a unit that resembles a normal air conditioner, ed.) in their apartment. So technically it is possible.
“If we can reduce the heat consumption in the building by 40% by isolating and regulating it, then we can reduce the price of heat by a third.”
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2024-01-10 22:24:12
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