In my passive house...

“It must be cold in winter,” said the classic. It turns out it's not necessary. In addition, in order to keep warm for a short time, it does not have to be dirty, smelly and harmful to the environment.

At present, we can have heat in our homes not necessarily due to fuel oil, gas and electricity. Solar, geothermal and even wind energy have joined the old mix of fuels and energy sources in recent years.

In this report, we will not touch on the still most popular systems based on coal, oil or gas in Poland, because the purpose of our study is not to present what we already know well, but to present modern, attractive alternatives in terms of environmental protection as well as energy savings.

Of course, heating based on the combustion of natural gas and its derivatives is also quite environmentally friendly. However, from the Polish point of view, it has the disadvantage that we do not have sufficient resources of this fuel for domestic needs.

Water and air

Most houses and residential buildings in Poland are heated by traditional boiler and radiator systems.

The central boiler is located in the heating center or individual boiler room of the building. Its work is based on the supply of steam or hot water through pipes to radiators located in the rooms. The classic radiator - cast iron vertical structure - is usually placed near the windows (1).

1. Traditional heater

In modern radiator systems, hot water is circulated to the radiators using electric pumps. The hot water releases its heat in the radiator and the cooled water returns to the boiler for further heating.

Radiators can be replaced with less "aggressive" panel or wall heaters from an aesthetic point of view - sometimes they are even called the so-called. decorative radiators, developed taking into account the design and decoration of the premises.

Radiators of this type are much lighter in weight (and usually in size) than radiators with cast iron fins. Currently, there are many types of radiators of this type on the market, differing mainly in external dimensions.

Many modern heating systems share common components with cooling equipment, and some provide both heating and cooling.

appointment HVAC (heating, ventilation and air conditioning) is used to describe everything and ventilation in a house. Regardless of which HVAC system is used, the purpose of all heating equipment is to use the thermal energy from the fuel source and transfer it to the living quarters to maintain a comfortable ambient temperature.

Heating systems use a variety of fuels such as natural gas, propane, heating oil, biofuels (such as wood) or electricity.

Forced air systems using blower oven, which supply heated air to various areas of the home through a network of ducts, are popular in North America (2).

2. System boiler room with forced air circulation

This is still a relatively rare solution in Poland. It is mainly used in new commercial buildings and in private homes, usually in combination with a fireplace. Forced air circulation systems (incl. mechanical ventilation with heat recovery) adjust the room temperature very quickly.

In cold weather, they serve as a heater, and in hot weather, they serve as a cooling air conditioning system. Typical for Europe and Poland, CO systems with stoves, boiler rooms, water and steam radiators are used only for heating.

Forced air systems usually also filter them to remove dust and allergens. Humidification (or drying) devices are also built into the system.

The disadvantages of these systems are the need to install ventilation ducts and reserve space for them in the walls. In addition, fans are sometimes noisy and moving air can spread allergens (if the unit is not properly maintained).

In addition to the systems most known to us, i.e. radiators and air supply units, there are others, mostly modern. It differs from hydronic central heating and forced ventilation systems in that it heats furniture and floors, not just the air.

Requires laying inside concrete floors or under wooden floors of plastic pipes designed for hot water. It is a quiet and overall energy efficient system. It does not heat up quickly, but retains heat longer.

There is also "floor tiling", which uses electrical installations installed under the floor (usually ceramic or stone tiles). They are less energy efficient than hot water systems and are typically only used in smaller spaces such as bathrooms.

Another, more modern type of heating. hydraulic system. Baseboard water heaters are mounted low on the wall so that they can draw in cold air from below the room, then heat it up and return it back inside. They operate at lower temperatures than many.

These systems also use a central boiler to heat water that flows through a piping system to discrete heating devices. In fact, this is an updated version of the old vertical radiator systems.

Electric panel radiators and other types are not commonly used in the main home heating systems. electric heatersmainly due to the high cost of electricity. However, they remain a popular supplementary heating option, for example in seasonal spaces (such as verandas).

Electric heaters are simple and inexpensive to install, requiring no piping, ventilation or other distribution devices.

In addition to conventional panel heaters, there are also electric radiant heaters (3) or heating lamps that transfer energy to objects with a lower temperature through electromagnetic radiation.

3. Infrared heater

Depending on the temperature of the radiating body, the wavelength of infrared radiation ranges from 780 nm to 1 mm. Electric infrared heaters radiate up to 86% of their input power as radiant energy. Almost all of the electrical energy collected is converted into infrared heat from the filament and sent further through the reflectors.

Geothermal Poland

Geothermal heating systems - very advanced, for example in Iceland, are of growing interestwhere under (IDDP) drilling engineers are plunging further and further into the planet's internal heat source.

In 2009, while drilling an EPDM, it accidentally spilled into a magma reservoir located about 2 km below the Earth's surface. Thus, the most powerful geothermal well in history with a capacity of about 30 MW of energy was obtained.

Scientists hope to reach the Mid-Atlantic Ridge, the longest mid-ocean ridge on Earth, a natural boundary between tectonic plates.

There, magma heats the sea water to a temperature of 1000°C, and the pressure is two hundred times higher than atmospheric pressure. Under such conditions, it is possible to generate supercritical steam with an energy output of 50 MW, which is about ten times greater than that of a typical geothermal well. This would mean the possibility of replenishment by 50 thousand. Houses.

If the project turned out to be effective, a similar one could be implemented in other parts of the world, for example, in Russia. in Japan or California.

4. Visualization of the so-called. shallow geothermal energy

Theoretically, Poland has very good geothermal conditions, since 80% of the country's territory is occupied by three geothermal provinces: Central European, Carpathian and Carpathian. However, the real possibilities of using geothermal waters concern 40% of the country's territory.

The water temperature of these reservoirs is 30-130°C (in some places even 200°C), and the depth of occurrence in sedimentary rocks is from 1 to 10 km. Natural outflow is very rare (Sudety - Cieplice, Löndek-Zdrój).

However, this is something else. deep geothermal with wells up to 5 km, and something else, the so-called. shallow geothermal, in which source heat is taken from the ground using a relatively shallow buried installation (4), usually from a few to 100 m.

These systems are based on heat pumps, which are the basis, similar to geothermal energy, for obtaining heat from water or air. It is estimated that there are already tens of thousands of such solutions in Poland, and their popularity is gradually growing.

The heat pump takes heat from outside and transfers it inside the house (5). Consumes less electricity than conventional heating systems. When it's warm outside, it can act as the opposite of an air conditioner.

5. Scheme of a simple compressor heat pump: 1) condenser, 2) throttle valve - or capillary, 3) evaporator, 4) compressor

A popular type of air source heat pump is the mini split system, also known as ductless. It is based on a relatively small external compressor unit and one or more indoor air handling units that can be easily added to rooms or remote areas of the home.

Heat pumps are recommended for installation in relatively mild climates. They remain less effective in very hot and very cold weather conditions.

Absorption heating and cooling systems they are powered not by electricity, but by solar energy, geothermal energy or natural gas. An absorption heat pump works in much the same way as any other heat pump, but it has a different energy source and uses an ammonia solution as the refrigerant.

Hybrids are better

Energy optimization has been successfully achieved in hybrid systems, which can also use heat pumps and renewable energy sources.

One form of the hybrid system is тепловой насос in combination with condensing boiler. The pump partially takes over the load while the heat demand is limited. When more heat is needed, the condensing boiler takes over the heating task. Similarly, a heat pump can be combined with a solid fuel boiler.

Another example of a hybrid system is the combination condensing unit with solar thermal system. Such a system can be installed in both existing and new buildings. If the owner of the installation wants more independence in terms of energy sources, the heat pump can be combined with a photovoltaic installation and thus use the electricity generated by their own home solutions for heating.

The solar installation provides cheap electricity to power the heat pump. Surplus electricity generated by electricity that is not used directly in the building can be used to charge the building's battery or sold to the public grid.

It is worth emphasizing that modern generators and thermal installations are usually equipped with internet interfaces and can be controlled remotely using an application on a tablet or smartphone, often from anywhere in the world, which additionally allows property owners to optimize and save costs.

There is nothing better than homemade energy

Of course, any heating system will need energy sources anyway. The trick is to make this the most economical and cheapest solution.

Ultimately, such functions have energy generated "at home" in models called microcogeneration () or microTPP ().

According to the definition, this is a technological process consisting in the combined production of heat and electricity (off-grid) based on the use of small and medium power connected devices.

Micro cogeneration can be used at all facilities where there is a simultaneous need for electricity and heat. The most common users of paired systems are both individual recipients (6) and hospitals and educational centers, sports centers, hotels and various public utilities.

6. Home energy system

Today, the average household power engineer already has several technologies for generating energy at home and in the yard: solar, wind and gas. (biogas - if they are really "own").

So you can mount on the roof, which are not to be confused with heat generators and which are most often used to heat water.

It can also reach small Wind turbinesfor individual needs. Most often they are placed on masts buried in the ground. The smallest of them, with a power of 300-600 W and a voltage of 24 V, can be installed on roofs, provided that their design is adapted to this.

In domestic conditions, power plants with a capacity of 3-5 kW are most often found, which, depending on needs, the number of users, etc. - should be enough for lighting, the operation of various household appliances, water pumps for CO and other smaller needs.

Systems with a thermal output below 10 kW and an electrical output of 1-5 kW are mainly used in individual households. The idea behind the operation of such a "home micro-CHP" is to place both the electricity and heat source inside the supplied building.

The technology for generating home wind energy is still being improved. For example, the small Honeywell windmills offered by WindTronics (7) with a shroud somewhat resembling a bicycle wheel with blades attached, about 180 cm in diameter, generate 2,752 kWh at an average wind speed of 10 m/s. Similar power is offered by Windspire turbines with an unusual vertical design.

7. Small Honeywell turbines mounted on the roof of a house

Among other technologies for obtaining energy from renewable sources, it is worth paying attention to biogas. This general term is used to describe combustible gases produced during the decomposition of organic compounds, such as sewage, domestic waste, manure, agricultural and agri-food industry waste, etc.

The technology originating from the old cogeneration, that is, the combined production of heat and electricity in combined heat and power plants, in its "small" version is quite young. The search for better and more efficient solutions is still ongoing. Currently, several major systems can be identified, including: reciprocating engines, gas turbines, Stirling engine systems, the organic Rankine cycle, and fuel cells.

Stirling engine converts heat into mechanical energy without a violent combustion process. The heat supply to the working fluid - gas is carried out by heating the outer wall of the heater. By supplying heat from outside, the engine can be supplied with primary energy from almost any source: petroleum compounds, coal, wood, all types of gaseous fuels, biomass and even solar energy.

This type of engine includes: two pistons (cold and warm), a regenerative heat exchanger and heat exchangers between the working fluid and external sources. One of the most important elements operating in the cycle is the regenerator, which takes the heat of the working fluid as it flows from the heated to the cooled space.

In these systems, the source of heat is mainly exhaust gases generated during the combustion of fuel. On the contrary, the heat from the circuit is transferred to the low-temperature source. Ultimately, the circulation efficiency depends on the temperature difference between these sources. The working fluid of this type of engine is helium or air.

The advantages of Stirling engines include: high overall efficiency, low noise level, fuel economy compared to other systems, low speed. Of course, we must not forget about the shortcomings, the main of which is the installation price.

Cogeneration mechanisms such as Rankine cycle (heat recovery in thermodynamic cycles) or a Stirling engine requires only heat to operate. Its source can be, for example, solar or geothermal energy. Generating electricity in this way using a collector and heat is cheaper than using photovoltaic cells.

Development work is also underway fuel cells and their use in cogeneration plants. One of the innovative solutions of this type on the market is ClearEdge. In addition to system-specific functions, this technology converts the gas in the cylinder to hydrogen using advanced technology. So there is no fire here.

The hydrogen cell produces electricity, which is also used to generate heat. Fuel cells are a new type of device that allows the chemical energy of a gaseous fuel (usually hydrogen or hydrocarbon fuel) to be converted with high efficiency through an electrochemical reaction into electricity and heat - without the need to burn gas and use mechanical energy, as is the case, for example, in engines or gas turbines.

Some elements can be powered not only by hydrogen, but also by natural gas or the so-called. reformate (reforming gas) obtained as a result of hydrocarbon fuel processing.

Hot water accumulator

We know that hot water, that is, heat, can be accumulated and stored in a special household container for some time. For example, they can often be seen next to solar collectors. However, not everyone may know that there is such a thing as large reserves of heatlike huge accumulators of energy (8).

8. Excellent heat accumulator in the Netherlands

Standard short-term storage tanks operate at atmospheric pressure. They are well insulated and are mainly used for demand management during peak hours. The temperature in such tanks is slightly below 100°C. It is worth adding that sometimes for the needs of the heating system, old oil tanks are converted into heat accumulators.

In 2015, the first German dual zone tray. This technology is patented by Bilfinger VAM..

The solution is based on the use of a flexible layer between the upper and lower water zones. The weight of the upper zone creates pressure on the lower zone, so that the water stored in it can have a temperature of more than 100°C. The water in the upper zone is correspondingly colder.

The advantages of this solution are a higher heat capacity while maintaining the same volume compared to an atmospheric tank, and at the same time lower costs associated with safety standards compared to pressure vessels.

In recent decades, decisions related to underground energy storage. The groundwater reservoir may be of concrete, steel or fibre-reinforced plastic construction. Concrete containers are built by pouring concrete on site or from prefabricated elements.

An additional coating (polymer or stainless steel) is usually installed on the inside of the hopper to ensure diffusion tightness. The heat-insulating layer is installed outside the container. There are also structures fixed only with gravel or dug directly into the ground, also into the aquifer.

Ecology and economics hand in hand

The heat in the house depends not only on how we heat it, but above all on how we protect it from heat loss and manage the energy in it. The reality of modern construction is the emphasis on energy efficiency, thanks to which the resulting objects meet the highest requirements both in terms of economy and operation.

This is a double "eco" - ecology and economy. Increasingly placed energy efficient buildings They are characterized by a compact body, in which the risk of so-called cold bridges, i.e. areas of heat loss. This is important in terms of obtaining the smallest indicators regarding the ratio of the area of ​​\uXNUMXb\uXNUMXbthe outer partitions, which are taken into account together with the floor on the ground, to the total heated volume.

Buffer surfaces, such as conservatories, should be attached to the entire structure. They concentrate the right amount of heat, while simultaneously giving it to the opposite wall of the building, which becomes not only its storage, but also a natural radiator.

In winter, this type of buffering protects the building from too cold air. Inside, the principle of a buffer layout of the premises is used - the rooms are located on the south side, and the utility rooms - on the north.

The basis of all energy-efficient houses is an appropriate low-temperature heating system. Mechanical ventilation with heat recovery is used, i.e. with recuperators, which, blowing the "used" air out, retain its heat to heat the fresh air blown into the building.

The standard reaches solar systems that allow you to heat water using solar energy. Investors who want to take full advantage of nature also install heat pumps.

One of the main tasks that all materials must perform is to ensure highest thermal insulation. Consequently, only warm external partitions are erected, which will allow the roof, walls and ceilings near the ground to have an appropriate heat transfer coefficient U.

Exterior walls should be at least two-layer, although a three-layer system is best for best results. Investments are also being made in windows of the highest quality, often with three panes and sufficiently wide thermally protected profiles. Any large windows are the prerogative of the south side of the building - on the north side, glazing is placed rather pointwise and in the smallest sizes.

Technology goes even further passive housesknown for several decades. The creators of this concept are Wolfgang Feist and Bo Adamson, who in 1988 at Lund University presented the first design of a building that requires almost no additional insulation, except for protection from solar energy. In Poland, the first passive structure was built in 2006 in Smolec near Wroclaw.

In passive structures, solar radiation, heat recovery from ventilation (recovery), and heat gains from internal sources such as electrical appliances and occupants are used to balance the building's heat demand. Only during periods of particularly low temperatures, additional heating of the air supplied to the premises is used.

A passive house is more of an idea, some kind of architectural design, than a specific technology and invention. This general definition includes many different building solutions that combine the desire to minimize energy demand - less than 15 kWh/m² per year - and heat loss.

To achieve these parameters and save money, all external partitions in the building are characterized by an extremely low heat transfer coefficient U. The outer shell of the building must be impervious to uncontrolled air leaks. Similarly, window joinery shows significantly lower heat loss than standard solutions.

The windows use various solutions to minimize losses, such as double glazing with an insulating argon layer between them or triple glazing. Passive technology also includes building houses with white or light-colored roofs that reflect solar energy in summer rather than absorbing it.

Green heating and cooling systems they take further steps forward. Passive systems maximize nature's ability to heat and cool without stoves or air conditioners. However, there are already concepts active houses – production of surplus energy. They use various mechanical heating and cooling systems powered by solar energy, geothermal energy or other sources, the so-called green energy.

Finding new ways to generate heat

Scientists are still looking for new energy solutions, the creative use of which could give us extraordinary new sources of energy, or at least ways to restore and preserve it.

A few months ago we wrote about the seemingly contradictory second law of thermodynamics. experiment prof. Andreas Schilling from the University of Zurich. He created a device that, using a Peltier module, cooled a nine-gram piece of copper from a temperature above 100 ° C to a temperature well below room temperature without an external power source.

Since it works for cooling, it must also heat, which can create opportunities for new, more efficient devices that do not require, for example, the installation of heat pumps.

In turn, professors Stefan Seeleke and Andreas Schütze from the University of Saarland have used these properties to create a highly efficient, environmentally friendly heating and cooling device based on the generation of heat or cooling of the driven wires. This system does not need any intermediate factors, which is its environmental advantage.

Doris Soong, assistant professor of architecture at the University of Southern California, wants to optimize building energy management with thermobimetallic coatings (9), intelligent materials that act like human skin - dynamically and quickly protect the room from the sun, providing self-ventilation or, if necessary, isolating it.

9. Doris Soong and bimetals

Using this technology, Sung developed a system thermoset windows. As the sun moves across the sky, each tile that makes up the system moves independently, uniformly with it, and all this optimizes the thermal regime in the room.

The building becomes like a living organism, which independently reacts to the amount of energy coming from outside. This is not the only idea for a "living" house, but it differs in that it does not require additional power for moving parts. The physical properties of the coating alone are sufficient.

Nearly two decades ago, a residential complex was built in Lindas, Sweden, near Gothenburg. without heating systems in the traditional sense (10). The idea of ​​living in houses without stoves and radiators in cool Scandinavia caused mixed feelings.

10. One of the passive houses without a heating system in Lindos, Sweden.

The idea of ​​a house was born in which, thanks to modern architectural solutions and materials, as well as appropriate adaptation to natural conditions, the traditional idea of ​​​​heat as a necessary result of connection with external infrastructure - heating, energy - or even with fuel suppliers was eliminated. If we begin to think the same way about the warmth in our own home, then we are on the right track.

So warm, warmer...hot!

Heat exchanger glossary

Central heating (CO) - in the modern sense means an installation in which heat is supplied to heating elements (radiators) located in the premises. Water, steam or air are used to distribute the heat. There are CO systems covering one apartment, a house, several buildings, and even entire cities. In installations spanning a single building, water is circulated by gravity as a result of density changes with temperature, although this can be forced by a pump. In larger installations, only forced circulation systems are used.

Boiler room - an industrial enterprise, the main task of which is the production of a high-temperature medium (most often water) for the city heating network. Traditional systems (boilers running on fossil fuels) are rare today. This is due to the fact that much higher efficiency is achieved with the combined production of heat and electricity in thermal power plants. On the other hand, the production of heat only using renewable energy sources is gaining popularity. Most often, geothermal energy is used for this purpose, but large-scale solar thermal installations are being built in which

collectors heat water for household needs.

Passive house, energy saving house – a construction standard characterized by high insulation parameters of external partitions and the use of a number of solutions aimed at minimizing energy consumption during operation. The energy demand in passive buildings is below 15 kWh/(m²·year), while in conventional houses it can even reach 120 kWh/(m²·year). In passive houses, the reduction in heat demand is so great that they do not use a traditional heating system, but only additional heating of the ventilation air. It is also used to balance heat demand.

solar radiation, heat recovery from ventilation (recovery), as well as heat gains from internal sources such as electrical appliances or even residents themselves.

Gzheinik (colloquially - a radiator, from French calorifère) - a water-air or steam-air heat exchanger, which is an element of a central heating system. Currently, panel radiators made of welded steel plates are most commonly used. In new central heating systems, finned radiators are practically no longer used, although in some solutions the modularity of the design allows the addition of more fins, and therefore a simple change in radiator power. Hot water or steam flows through the heater, which usually do not come directly from the CHP. The water that feeds the entire installation is heated in a heat exchanger with water from the heating network or in a boiler, and then goes to heat receivers, such as radiators.

Central heating boiler - a device for burning solid fuel (coal, wood, coke, etc.), gaseous (natural gas, LPG), fuel oil (fuel oil) in order to heat the coolant (usually water) circulating in the CH circuit. In common parlance, a central heating boiler is incorrectly referred to as a stove. Unlike a furnace, which gives off the generated heat to the environment, the boiler gives off the heat of the substance that carries it, and the heated body goes to another place, for example, to a heater, where it is used.

condensing boiler - a device with a closed combustion chamber. Boilers of this type receive an additional amount of heat from flue gases, which in traditional boilers exit through the chimney. Thanks to this, they operate with a higher efficiency, reaching up to 109%, while in traditional models it is up to 90% - i.e. they use fuel better, which translates into lower heating costs. The effect of condensing boilers is best seen in the flue gas temperature. In traditional boilers, the temperature of flue gases is more than 100°C, and in condensing boilers it is only 45-60°C.