HVAC systems
This article confirms a comparative study between the main types of air conditioning systems in existing buildings on the market by analyzing the different equipment that is characterized by the types of facilities that we can find and distinguishing the uses of each air conditioning installation in particular.
This technology is based on the treatment of air to obtain a simultaneous control of humidity, temperature, cleanliness and a distribution in the interior spaces such as in a room or in a building.
Classification
The classification of air conditioning systems They can be named according to the system they use to take primary energy or give it up. Given the casuistry, we will distinguish them according to:
- Air - Air systems (All air installations)
- Air - Water systems
- The Water - Water systems (All water installations)
- Water - Air systems
When we speak of a network by means of Air-Air or Air-Water and Water-Water or Water-Air, the first concept-term is based on the exchange fluid with that outdoor unit (Outdoor) and the second attending to the indoor unit. Actually, it is named at the beginning, the medium with which the equipment is condensed, when we are giving cold to the cabin that we want to air-condition, that is:
- EL Air - Air: Exchange in the installation with air between both units.
- Air - Water: Exchange in the installation with air in the outdoor unit and with water in the indoor unit.
- Water - Water: Exchange in the installation with water between both units.
- Water - Air: Exchange in the installation with water in the outdoor unit and with air in the indoor unit.
Before this little introduction about the air-conditioning system There is a question that is interpretable … Does the primary circuit correspond to that indoor unit and the secondary one to the outdoor one? From an exchanger there is a primary fluid that actually exchanges its heat to try to change that temperature. We would call this fluid that causes this alteration in another, primary, and the modified altered is secondary.
We remember that we have an interesting article about the different types of glazing in homes that may be of interest.
What is an Air-Air system?
The air conditioning systems The most common can be found in the field of residential construction, shops or, for example, small-power banking entities.
These installations can be seen in the false ceilings and walls connected to air diffusers and ducts having an outdoor unit normally connected by insulated copper pipes with the relevant drains. Not many years ago, we could also find them sometimes installed in the windows, with the external part exchanging the heat.
We can see better how an air-to-air equipment works in the following diagram of a air conditioning installation:
In the face of all-air systems, speaking of those with more power, we can find them in different types of power plants, taking into account their normal operation we have the following types of air conditioning equipment.
Air - Air system types
- The centrals with constant air flow Air - Air. This installation works by introducing air into the premises, with the same flow rate and gradually regulating the power to be supplied, varying the temperature at which it is supplied and the time.
- The centrals with variable air flow Air - Air. These facilities are based on adjusting the amount of energy provided, changing the amount of air introduced into the cabin itself, that is, the flow.
A example of air conditioning With these systems we can see it in the following infographic to clarify the concepts based on the different types of air conditioning:
We can see the interactive infographic scheme on the installation for air conditioning from here.
This is where the VRF units come in - Variable Refrigeration Volume, which can work in hot or cold mode and also, with the effect of heat recovery.
As mentioned above, the air-conditioned equipment from the internal part they receive liquid to produce cold, expand and in the same circuit, some act in the form of condensers providing heat. From the external unit it will function as evaporator and condenser according to the requirements of all the air conditioners as a whole.
These air conditioning systems for houses, They also use inverter drive compressors, that is, it changes the rotation speed according to energy consumption (portable and compact equipment usually does not, we can the article on types of portable air conditioning)
Comparatively, it reduces electricity consumption with respect to other systems and processes in a substantial way, which is equivalent to that the COP (We can see from the article what is the COP and the inverter heat pump), what are the thermal watts provided divided by watts consumed, in intermediate loads it is much higher.
It must be taken into account that technology and R&D are advancing in giant steps, refining techniques in search of greater energy efficiency and effectiveness in equipment on the differenttypes of air conditioning systems.
What is asAir - Water system?
They are facilities that use fluid or water as a base component for the supply of hot or cold energy in front of batteries that exchange heat with air, conditioning it. The terminal machines can be inductors, fan-coils, radiators, central air conditioners for installations with more power, convectors … etc.
But, What is the difference between Air - Air and Air - Water equipment?… The Air - Air equipment it does not heat any water circuit, but directly the air. So an Air - Air equipment is somewhat limited, since they only serve to heat the air, so they do not serve to heat sanitary hot water, but only as heating by means of the expulsion of hot and also cold air, if that is the case. I'd like.
Mainly the parts - components of an air-water air conditioning unit are: Thermal power station + Water distribution + Terminal elements + Regulation elements. To see it a little better from the section on energy efficiency, heat pumps, air conditioning and heating of Panasonic we have some clear examples with modern equipment with reference to residential:
For a example of individual installation in homes (A floor) with its components:
For a example of community installation - collective (A building) with its components:
Types of Air - Water systems
The different types of Air-Water systems are found depending on the fluid flow, if it is variable or constant. So we will have:
- Central systems with constant air flow Air - Water
- Central systems with variable air flow Air - Water
- Central systems with constant volume of multi-zone distribution at different temperatures
In the following video, it is explained how an air conditioner works (air treatment unit) by water, and which elements the air temperature is regulated to obtain the best comfort conditions and energy savings.
What is asWater - Water system?
The production of heat or cold is based on the fact that for the capture or transfer of heat to the fluid, water or heated or cooled fluid is used, either with combustion in boilers, with heat from the outside to pass it through the water for air conditioning.
These facilities within the types of air conditioning for buildings and equipment, also known as hydronics, will require circuits similar to cooling towers, well water, geothermal and other similar techniques to achieve the condensation of the compression cycle.
Identifying how an installation with a water-water system works We could define it as; uses the water itself as a carrier of heat or cold and a terminal unit that takes advantage of that temperature to condition a cabin or area. These systems require other elements such as water chillers, fan coils, boilers or heat pumps.
But, What is the difference between a Water - Water (All water) team and the previous ones mentioned?… The main difference with the previous systems that we have seen, is that Air is not used to acclimatize a space.
When we use water for the condensation of the producing groups, we achieve lower temperatures and are even more stable than ambient air. When temperatures are more stable in the compression cycle, they can significantly increase and improve the efficiency of the facilities.
For example, if we use a geothermal chiller, that is, 15ºC (+/- 2ºC) all year round. In cold winter rooms we can heat them in the ventilation air and, in summer, pre-cool it. Thus, the energy cost is practically free.
What is asWater - Air system?
The operation of the Water - Air facilities (Also commonly called Water - Environment equipment) are providing the heat basically by transmission and radiation. The types of radiation elements are varied with different alternatives.
Most common types of Water - Air systems
- Radiant ceilings
- Underfloor heating
- Convectors and radiators
Air zoning
The zoning in air conditioning at all times pursues that energy saving using a main base where each room represents an independent microclimate and that must be managed in such a way.
In the market we can find systems adaptable to zoning according to environments and needs. The objective is to find comfort where the degrees can be adapted and today with the technology we have we can already use zoning systems with home automation control (See article with examples of home automation installations for homes) in homes that also offer multiple advantages and possible interactions with other facilities.
Generally, any of the air conditioning installations that a home may have can be adapted for zoned control (See article on thermostats for home heating), with more or less investment and modifications. Some examples are presented:
- Underfloor zoning: underfloor heating is a system with very slow thermal inertia, so special attention must be paid to control by presence detection, it is not convenient to activate and deactivate it continuously. It is necessary to install independent circuits for each room, with their corresponding control valves. An adequate water balance is essential, which takes into account the operation or not of different areas at the same time.
- Zoning with Fan Coil: in this case, the thermal inertia is faster, thanks to the contribution of the fans, in addition to the circulation of water through the pipes. There must be at least one unit in each room.
- Zoning with A / C units (splits): it is necessary to install at least one indoor unit per room to be air-conditioned. Both can be achieved using the “multi-split” system or the more efficient and innovative “VRV”, developed by the Daikin company. The difference between one and the other is the management of the volume of refrigerant liquid sent to each indoor unit, being variable in the case of VRV (Variable Refrigerant Volume).
- Zoning with large A / C unit and ducted dispersion: with a large A / C machine, the air flow is distributed through thermally insulated ducts, and its flow is controlled in each room with motorized louvers.
Remember that within the technology that we can install in the home, we also have thermostatic control, that is, the famous digital thermostats for heating in homes that will save us a few euros by controlling the temperature of the rooms.
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Some articles of interest:
- Aerothermal heat pumps
- Pellet stoves, types and examples
- Aerothermal heating, cooling and ACC
- What is energy saving and how is it promoted?
- How to save on heating
- heat recovery units and their advantages
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