Project of the refrigeration unit

Our design company has developed the design documentation for the refrigeration center of the office building .

hc refrigeration center project

 

DESIGN REFRIGERATION CENTER

The air conditioning system of chiller-fancoil type is designed for cold supply of offices, public catering enterprises, apart-hotel. On the 5th floor of the complex there is a refrigerating center. The calculated refrigeration load of 3500 kW is determined under the conditions of cooling all consumers of the complex in the hour of maximum heat gains taking into account the orientation of the facades of the building.  

The composition of the refrigeration center includes refrigerators (chillers) with air-cooled condensers, heat exchangers and hydromodules for them in the buffer tanks, accumulator tanks, shut-off and control valves. Also in the refrigeration center room, a tank for draining polypropylene glycol is to be located. Dry cooling towers are installed in the open area, on the roof of the building.

Water cooling is carried out in the warm period of the year with 3 chillers with capacity 1125kW each. At the same time one chiller with heat recovery for DHW preparation. Provided refrigeration machines OMEGA V ECHOS LN-153.3 imported production Blue Box (Italy). The machines are working on ozone-safe freon R134a.

The machines are made in the low-noise version - the sound insulation of the compressor is made of painted sheet steel covered with absorbent material.   The refrigeration circuit consists of independent refrigeration circuits with compressor discharge line shutoff valve, liquid line shutoff valve, charging valve, sight glass, filter drier, electronic thermostatic expansion valve, high and low pressure switches and safety valve. 

The chiller is equipped with a semi-hermetic single-screw compressor with a continuous capacity adjustment range of 30-100%. Each compressor is equipped with a crankcase heater and built-in electronic protection system with temperature sensors located directly on the motor winding and in the discharge piping.

Starting and stopping of the unit is done with 12% capacity control and by switching the electrical windings from star to delta. A shell-and-tube evaporator with dry steam exhaust, insulated by a casing of sealed porous material, with anti-freeze protection system.  The condenser is a shell-and-tube heat exchanger. 

In the control cabinet there are: input switch, fuses and circuit breakers of power and control circuits, compressor starters. Microprocessor controller, to which the display can be connected. Equipment is factory tested and charged with refrigerant and oil. 

Cooling of the cooling machine condensers is carried out by circulating a 45% solution of polypropylene glycol in a closed circuit through external dry coolers, imported TERMO KEY (Italy). The coolant of the secondary circuit of the refrigeration system is water with the temperature parameters of 7/12 0C. The cooling machines have the possibility of capacity regulation depending on the load on the system.

When the ambient air temperature drops to +1...3 0C, the refrigeration center automatically switches to the free cooling mode "Free cooling", in which the cooled glycol after the external dry coolers is pumped into the heat exchanger and cools the water down to 7 0C.

The refrigeration system includes frequency controlled pumps, which together with the control valves reduces the electrical load associated with the operation of circulation pumps. The cooling system is fully automated, it is possible to remotely control and manage the equipment from the control room.

2.     FIRE PROTECTION MEASURES

Fire safety in the refrigerating center shall be ensured by the following design solutions:

  • pipelines in the places of intersection of ceilings, internal walls and partitions are laid in metal sleeves with subsequent caulking of gaps with noncombustible materials to ensure the rated fire resistance limit of the enclosure;

  • the heat insulation is made of non-combustible materials. 

    Fire safety in the systems of general ventilation and air conditioning is provided by the following design solutions:

  • installation of fire dampers KLOP-2 with electromechanical drive Belimo with the rated fire-resistance limits at the points where the ducts cross fire barriers (walls and ceilings). All dampers are adopted with fire resistance limit EI60;

When ducts cross partitions with non-standard fire resistance rating, the gap between the wall and the duct must be tightly sealed with non-combustible materials. When ducts cross fire walls, partitions and ceilings, normally open fire dampers with fire resistance rating must be installed in accordance with regulations.

The system of supply and exhaust ventilation is automatically turned off when there is a fire in the building and the smoke exhaust and air overpressure systems are automatically activated. In addition, manual activation of the systems in case of fire is envisaged.

 3. MEASURES TO PROTECT AGAINST NOISE AND VIBRATION

The project includes necessary measures for excluding penetration of noise and vibrations from the operating equipment of the refrigeration systems into the serviced premises of the building and the adjacent territory with observance of the requirements necessary according to the sanitary norms in force СН 2.2.4/2.1.8.562-96 "Noise at Work, in Residential and Public Buildings and Territories of Residential Building".

These measures include:

  • Refrigeration equipment shall be installed in soundproofed rooms;

  • Chillers shall be of low-noise design and insulated with noise-absorbing material;


  • Piping shall be secured with rubber gaskets;

  • The velocity of the coolant movement in the pipelines is taken not more than the values established by SNiP 41-01-2003 (2.04.05-91*);

  • Pumps of cold supply system are installed on foundations, flexible inserts (rubber compensators) are used to connect the pumps to the pipelines;

  • Before installation on site the pumps are subject to test run to check the bearings and alignment of the wheels;

  • Duct fan coils are connected to the grilles by means of flexible soundproofed ducts;

  • indoor units VRV indoor VRV units are sized for average fan speed.

ENERGY SAVING MEASURES

In order to save energy resources, the following solutions were applied in the project:

  • All external enclosures (walls, coverings, windows) are made with regard to energy saving conditions in accordance with SNiP 23-02-2003.  The constructions of the enclosures are specified in the architectural and construction section of the project;

  • all pipelines are covered with high efficiency insulation;

  • use of fans and pumps with frequency controlled drives;

  • installation of systems for autoregulation of cold consumption by central air conditioners, fan coils.

 AUTOMATIZATION OF "HVAC and AC" SYSTEMS

 The project provides for automation of the following subsystems as part of the refrigeration system
- chillers;
- dry coolers;
- pump groups of chillers;
- pump groups of fencoils;
- pump groups of ventilation cooling circuits;
- pressure maintenance pump groups;
- 2-way and 3-way valves.

Automation and dispatching system performs the following functions:

  • architectural and construction section of the project;

  • automatic change of winter/summer operation modes;

  • automatic change of equipment working / standby;

  • automatic change of equipment working/standby;

  • control of the state of elements of the refrigeration system and technological parameters (air and water temperature etc);

  • prevention of emergency situations;

  • remote control and monitoring of operation;

  • control of the energy consumption (refrigeration, electric power);

  • automatic shutdown of the refrigeration center and refrigeration supply systems in case of fire with simultaneous automatic activation of the smoke removal and pressurization systems;

  • control of the engineering systems parameters from the central control room. 

      Automatic control mode of systems operation is duplicated by manual control. The choice of control mode is made by the service of building engineering systems operation. 

EQUIPMENT AND MATERIALS

This stage of the Project envisages use of domestic and imported equipment and materials.

All equipment and materials used for the construction of the complex is certified for use in the Russian Federation.