As regards air-conditioning, large spaces typical for offices, hotels or public utility buildings, are a specific challenge. Certainly, in each case, no matter the investment’s scale, a particular importance is attached to energetic effectiveness of the system as well as its functionality and aesthetics. In large installations, structural aspects and flexibility of the system are of a great importance. Nowadays, air-conditioning industry offers a number of new solutions which are the answer for the market problems and demands of the clients as mentioned above.
Big can more
For a long time, air-conditioning systems, based on variable refrigerant flow technology (VRF), have gained ground in offices. They are appropriate wherever specific demands of vast multilevel installation are supposed to come up. Reputable producers compete with each other in the area of possible differences in a level between inside and outside units (even several dozen meters) or reached lengths of pipelines within single installation. In the last case, record-holders enable to conduct the tubing with a total length reaching even 1000 m as in a technology offered by Mitsubishi Heavy Industries, Ltd (MHI) Inverter Multi-System.
The limit of a number of inside devices in a system as well as the range of their available types increase complementary to the development of the range of air-conditioning structures VRF. Producers offering installations with considerable total length of pipelines often dispose of the biggest choice of inside units’ types and models, which can be connected to the structure in any configuration. Modern products, belonging to the discussed group of air-conditioning installations, rise to the challenge in an intelligent building – their steering standards meet the requirements of contemporary BMS systems.
Integration does not have one name
A meaningful advantage of high class systems, including VRF, is their effective work even in conditions of a low ambient temperature. For instance, VRF Inverter Multi-System, developed by MHI proves even during twenty-degree freeze! Technical innovations enabling an effective functioning of air-conditioning systems in such unfavourable conditions let on a dynamic development of their heating function. Noteworthy solutions are currently characterized by ability of simultaneous heating and cooling of particular spaces within the system and ordering of heat waste at the same time. The example is here a tripipeline system KXR6 with a function of heat recovery generated during a heating function as well as released on a condenser.
Worth considering method of heat waste reduction is the integration of air-conditioning system and ventilation with recuperation. Depending on the case (heating/cooling), a direction of the heating flow in exchanger of a recuperative centrals is reversed – in winter, the air which is removed from spaces heats the steam of a fresh and cool air, in summer – the other way round. A very interesting are Freon changers of heat with an expansion valve (for instance, SAF-DX, MHI). This device may power a recuperative central in heat and cool, while steering its work is realized from a level of an outside unit of an air-conditioning system.
In many cases, except for the fact that some parts of the building must be extra warmed, whereas the other require a cool supply, the production of warm municipal water (CWU) is necessary for the whole year. Integrated installations may be the solution, i.a. configured in a four-pipeline structure, EXP systems (Rhoss SpA) enabling the building of an entire air-conditioning system with a function of CWU production with the use of only one device with heat recovery. It allows on the reduction of compressor supply costs with keeping satisfactory energetic efficiency and effectiveness.
Not only VRF
Vast systems, such as VRF Inverter Multi-System, are currently opposed to alternative solutions like Multi-Split, useful in slightly different applications. Inverter Multi-Split, offered by MHI, is a structure of inside inverter units (to 6 pieces), connected with one outside unit. Crucial for this system is a possibility of individual steering of work parameters of certain units inside rooms and modular structure (multiply of systems 1+ max 6). Therefore, the system may effectively control the supply in cool or heat of many small, neighbouring offices or apartments. Cool distributors may be even 25 m away from an outside unit, while the maximum difference in level is 20 m.
If a large utility local is the subject of an investment (for instance, a conference hall, restaurant etc.), an alternative V-Multi system is noteworthy. Its characteristic feature is simultaneous work of few inside units. The maximal cooling efficiency of outside centrals, in comparison with Inverter Multi-Split, is twice higher (V-Multi do 25kW, Inverter Multi-Split do 12,5kW) and the length of a pipeline connecting distributors with an outside unit, in the case of innovative Hyper Inverter central, may reach even 100 m.
Modern technologies in respect of fan coil units
Innovative products in this category of devices are i.a. inverter fan coil units, equipped with brushless engine of a direct current (for instance, a device offered by Rhoss Sp. A.). Electrically steering commutator replaces brushes here. Thanks to such approach, one of the most emergency elements of a device has been eliminated. Another advantages of the solution are quiet work, higher efficiency of energy conversion, the lack of necessity of providing the circulation of air in the area of coils (the heat is transferred through the jacket, which may be more airtight in this case), higher heat comfort and energy saving of 50 per cent towards traditional solutions.