What to choose — water-cooled air conditioners or a chiller-fan coil system?

The rational organization of engineering systems and communications, which is based on a detailed analysis of the architectural and functional features of the building, can reduce capital costs, increase reliability and reduce energy consumption of climate control equipment. At the same time, many other factors influence the choice of how to implement building engineering systems, for example, the time the building is put into operation, or the forms of organization of business processes that will take place in the building. The model range of Dantex climatic equipment makes it possible to create professional air conditioning systems (hereinafter referred to as ACS) from various components that meet the requirements of modern business projects. This article shows the benefits of Dantex in two SCR options. In these two examples, the equipment performs the function of air conditioning — cooling the air in the office premises. In the first case, Dantex chillers and fan coil units are used. In the second case, the air conditioning system is built on the basis of water-cooled condenser air conditioners and dry coolers.

Centralized and decentralized air conditioning systems

One of the trends in the history of the development of engineering systems and communications is centralization or, in other words, the redistribution of functions between various components in such a way that individual processes, such as cooling several rooms or the entire building, are performed centrally — resources common to these rooms.

As can be seen from the figure, the air conditioning system in the first example includes one chiller placed outside the building. It cools the water in the SCR hydraulic circuit, which is then used in air handling units — fan coil units. Cassette fan coil units are installed inside air-conditioned rooms and provide cooling and air filtration inside the working areas. The hydraulic circuit consists of circulation pumps, an expansion tank and an accumulation tank and distributes the water cooled by the chiller throughout the building between the fan coil units.

The Dantex range of equipment for central air conditioning systems includes several types of water coolers:

— Monoblock chillers with air cooling of the condenser. The range covers the performance range from 5 to 1500 kW.

— Modular air-cooled chillers. Modules are released capacity 30, 65, 130, 185, 250, 260, 450, 600, 720, 810, 900 kW.

— Chillers with water cooling of the condenser, and also chillers without condenser with a productivity from 5 to 1300 kW.

Air handling units — fan coil units.

The range of fan coil units of the Standart and Profi series includes both fan coil units of European production, as well as cassette, duct, wall, floor and ceiling equipment with a capacity of 1 to 30 kW, manufactured in other countries.

Decentralized air conditioning systems

Decentralization of air conditioning processes is a redistribution of functions common to the system in favor of individual air conditioning systems distributed throughout the building. The use of decentralized systems allows you to increase reliability, reduce the initial cost of hard currency and redistribute it towards the owners of the premises, improve performance.

The air conditioning system in this case includes air conditioners with water-cooled condenser duct and console versions. They perform the function of cooling, heating and filtering the air. The hydraulic circuit for cooling the condenser removes the heat generated as a result of the operation of air conditioners, and consists of a pipeline, shut-off and control valves and circulation pumps. The drycooler is installed outside the building and provides cooling for the water in the condenser cooling hydraulic circuit.

The air conditioner with water cooling of the condenser is a monoblock unit, which is equipped with an independent refrigeration unit (refrigeration circuit of the refrigerant circulation), a fan, an automated control system and other elements.

The range of Dantex water-cooled air conditioners covers the performance range from 2 to 30 kW and includes two series. The DZ-VUSTIL series are duct units designed for concealed installation. The DZ-VUSTIK series are console units designed for floor installation.

Functional features and advantages of two different options for organizing SCR

Criteria	SCR No. 1 based on chillers and fan coil units	SCR No. 2 based on air conditioners with water-cooled condenser.	Comparison
Cooler — refrigeration unit	The chiller cools the water in the SCR hydraulic circuit, which then enters the fan coil units to cool the air in the premises.	Each water-cooled air conditioner has an independent refrigeration circuit that cools the air inside the air-conditioned rooms.	The use of one high-capacity chiller in SCR No. 1 reduces the cost proper air conditioning system, simplifies maintenance. Since in SCR No. 2 coolers — refrigeration units are built into each air conditioner, all rooms are independent. This improves reliability and reduces power consumption.
Heat distribution in the building	The distribution of heat in the building is carried out using a hydraulic circuit in which cold water circulates at a temperature of 7-12C	The distribution of heat in the building is carried out using a hydraulic circuit for cooling the condensers of air conditioners, in which warm water circulates at a temperature of 42-47C	In SLE No. 1, there are increased requirements for thermal insulation. In addition, the chiller’s hydraulic circuit must be equipped with a storage tank, which increases the cost and energy waste. In the second case, there is no need for additional thermal insulation.
Cooling and heating	SCR No. 1 can only work in cooling mode or in heating mode.	Each room can be set to its own operating mode — cooling or heating	Installation in each room of an independent air conditioner with water cooling of the condenser expands the ability of the SCR to maintain individual comfort conditions.
Work during winter periods	There are limitations on the temperature range of operation of the equipment in the winter period when operating in cooling and heat pump mode.	There are restrictions on the temperature range of operation of the equipment in the winter when operating only in the heat pump mode.	The use of air conditioners with water-cooled condenser reduces the sensitivity of the SCR to the effects of negative temperatures.
Gradual commissioning of SCR	Since the chiller is the most expensive element of the SCR, most of the costs are incurred in the pre-commissioning phase of the SCR.	The main costs will be distributed over the time of the phased commissioning of the system.	SLE 2 is most attractive at sites with a phased commissioning, for example, in multifunctional office complexes in which individual premises will be owned by individual tenants. When organizing SCR-2, the initial investment is associated with the purchase of an inexpensive cooling tower and elements of the condenser hydraulic circuit. While the future owners, at their discretion, will be able to equip the premises with the necessary air conditioning, depending on the functional and architectural features.

Source: TD «White Guard»