Human awareness versus energy-efficiency
Increasing human awareness and European Union requirements concerning ecology and energy-efficiency, to some extent, force people to apply solutions of technical installations which have not been very commonly used so far.
Alternative energy and heating sources are becoming more and more popular. These sources utilize renewable energy sources such as different kinds of heating pumps, solar collectors, photovoltaic panels and wind power plants. Mechanical ventilation system is already a norm in energy-efficient building engineering.
Properly selected installation solutions help to decrease significantly building maintenance costs and they can have positive influence on the natural environment.
Mechanical ventilation with heat recovery
The recuperator is responsible, first of all, for heat recovery coming from air blown out of the building and, secondly, for transmitting it to fresh air which is taken into the building.
It improves the air quality inside the building and has positive effect on the comfort sensation and occupants’ general physical and mental state. It also prevents accumulation of moisture and occurrence of bacteria and fungi.
Ventilation system which is designed and executed well allows to recover 95 % of heat coming from blowing air. Contrary to gravity ventilation, it helps to decrease heating costs of the building.
It is an electrical device which takes heat from the outside environment (air, water, soil) and transmits it to the domestic heating systems.
This energy can be used to heat up domestic water and the building itself.
Heat pump allows to reduce expenses connected with heating even up to 50 %.
It is the most effective while used in connection with underfloor (water) heating. Heat pump operation does not cause emitting the fumes, it does not pollute the environment, and that’s why it is very an ecological solution.
The device is virtually maintenance-free, which makes it more convenient in usage.
Wind power plant
It is the system generating electricity from movement of air masses. The most popular are turbines with horizontal axis of rotation, which reach the efficiency max up to 80 %, and turbines with vertical axis of rotation, which reach the efficiency up to 40 %.
Power generated by the power plant depends on location, the lie of the land, height of plant mast, season and time of the day, among other things. In summer season wind power plant will generate 40 % of annual energy but in winter season 60 % of annual energy.
The best way to utilize energy gained from wind is to channel it to heat domestic water as it does not cause big heat loss
For example, power plant with 1 kW turbine generates about 4-5 kWh within 24 hours. It allows for work of eight 100 wattage light bulbs for 6 hours a day or supply of other electric devices. Wind power plant investment allows to pay for itself within about 6 years.
They convert sun’s radiation into usable electricity. They can be used as an independent source of energy (off-grid) which stores gained energy in accumulators and then they transfer the energy to electric devices.
Generated energy (or its sulprus) can be transferred to on-grid network. Both these solutions are really beneficial for the investor for financial (lower bills for electricity and heating) and environmental reasons because we use fully-renewable and eco-friendly energy sources.
Unlike solar collectors, they can also work on cloudy day. Cost of investment is unfortunately quite high. However, prices are getting lower very quickly, which makes it more popular and cost-effective solution.
Principle of operation is similar to photovoltaic panels. However, solar collectors convert solar energy into heat energy which is used to heat up domestic water.
If the weather is cloudy and in winter season, level of solar panels output is very low. It means that practically they will not be able to heat domestic water. The maintenance cost of solar collectors is relatively low in comparison to the advantages resulting from using them.
Solar collectors investment is definitely less expensive than photovoltaic panels investment. The investment can pay for itself after a few or dozens of years, depending on type of the main heating source, number of users etc.
Radiator central heating versus underfloor heating. Which way of heating should we choose?
Choice of heating system has essential influence on many factors related to the building and its utilization: cost of heating, users’ thermal comfort and building aesthetics, among other things.
When choosing heating system we should take into consideration building’s source of energy, heat its insulation, and cost of installation workmanship.
Below, there are advantages and disadvantages of both these heating systems.
Underfloor heating :
+ It provides regular and optimal temperature distribution in the building
+ High thermal comfort for users
+ It cooperates perfectly with heat sources of low temperature (heat pumps, condensing boiler)
+ Lower energy consumption
+ Installation is invisible, hidden under the floor
+ After disconnecting the heat source, it maintains definite temperature for a few hours
- It takes a lot of time to heat up the installation
- In places where the underfloor heating is used, carpets, sheet flooring or other insulation materials should not be put as they reduce performance of the installation
- It requires professional workmanship of the installation
- Higher costs of workmanship
Radiator central heating:
+ Easy regulation of performance/ efficiency
+ Matching a radiator to each room (heating power is optimised)
+ Lower cost of installation workmanship in comparison to underfloor heating
+ Faster and easier way of assembly
+ Radiators can serve as decorative elements
- They take space in a room
- Irregular temperature distribution, which influences heat comfort
- Disconnection of heat source makes them stop transmitting heat to the place
Choice of heating system should depend on type of building’s heating source. Application of radiator central heating can be taken into consideration in rooms of small undeveloped floor space.
It is not advisable to combine these two heating systems on the same floor of the building.
Can fireplaces be used in energy-efficient buildings?
Fireplaces can be used in buildings of energy-efficient standard. Mainly, however, they do not serve as independent building’s heating system but rather as a supplement or alternative heating in case of main heat source break-down.
However, they are ideal to spend winter evenings with relatives in front of them as they make the place more charming.
In passive buildings fireplace installation is not advisable because it causes too much energy loss through a chimney.
Energy-efficient windows; coefficient of the window versus coefficient of window glazing (Uw or Ug?).
Application of energy-efficient windows has become a norm in building engineering regardless of the technology.
When choosing windows, we should pay attention to a few parameters. The most important factor defining energy-efficiency of windows is UW heat transmission expressed in W (m2 *K).
The lower UW coefficient is, the more energy-efficient windows are. UG coefficient defines heat transmission for the glass itself and it is lower than UW coefficient. For marketing purposes it is commonly used by salespeople because glass coefficient is given rather than window coefficient. That’s why when choosing windows, we should pay attention to UW coefficient rather than UG one.
When selecting PCV windows, it is worth paying attention to :
- Main wall thickness because it has impact on statics and strength of windows
- Thickness of steel reinforcing, which stiffens the profile
- Quantity of ferrules elements and their producer (it can improve users’ comfort)