Uniflair Serie BRA
Available versions and options 1/2 BRAC – Cooling only • Basic version; • Low noise version:produced by means of limiting the fan speed and sound-proofing of the scroll compressors, or a soundproofed hood and dampers for the screw compressors. • Basic version; • Low noise version: produced by means of limiting the fan speed and sound-proofing of the scroll compressors, a soundproofed hood and dampers for the screw compressors. • Ultra low noise version: produced by further limiting the fan speed and sound-proofing of the scroll compressors, a soundproofed hood and dampers for the screw compressors. (fan speed regulator on all standard fans). BRAT – Cooling only for high temperatures • Basic version with fan speed regulation on all of the standard fans; • Low noise version: produced by means of limiting the fan speed and sound-proofing of the scroll compressors, or a soundproofed hood and dampers for the screw compressors. (fan speed regulator on all standard fans). BRAF – Free Cooling
Available versions and options 1/2 BRAM – Ultra low noise Free Cooling • Basic version; • Low noise version:produced by means of limiting the fan speed and sound-proofing of the scroll compressors, or a soundproofed hood and dampers for the screw compressors. (fan speed regulator on all standard fans). BRAH – Heat pumps • Basic version with fan speed regulation on all standard fans; • Ultra low noise version: produced by means of limiting the fan speed and sound-proofing of the scroll compressors, or a soundproofed hood and dampers for the screw compressors. (fan speed regulator on all standard fans).
Fans Condensing coils Compressors Compressors Thermostatic Valve Brac / Brat units with Scroll Compressors 6 STEPS
Energy efficiency at partial loads All Uniflair chillers and heat pumps have been designed in order to optimise the modulation of the cooling capacity (thermal) and provide elevated efficiency during operation at partial loads. The 1206A÷1506A units are equipped with 6 scroll compressors connected in parallel in groups of 3 on two refrigerant circuits: the units provide at any time 6 partialization steps, ensuring accurate regulation of the discharge water. The 1802A÷3002A are equipped with 2 screw compressors connected in parallel on two refrigerant circuits; each compressor can be regulated with 4 steps or continuously (optional) and therefore the standard unit provides 8 partialization steps, ensuring accurate regulation of the chilled water.
Energy efficiency at partial loads - SCROLL The models in the new range with capacities up to 400kW are equipped with sixSCROLL rotary compressors, connectedintandem. All of the models have two independent refrigerant circuits, guaranteeing at least 50% of the cooling capacity in the event of problems with one of the two circuits as well as elevated energy performance at partial loads.
Energy efficiency at partial loads - SCREW Models which have a cooling capacity higher than 400 kW are equipped with two double compact screw compressors. They feature a temperature sensor placed on the windings against thermal overload, a check valve on the discharge to stop inverse rotation of the screws to allow equalisation of the pressure within the compressors and for no-load start-up. Both of the compressors are equipped with 4 partialization steps (0 – 25 – 50 – 75 – 100%) and therefore the outlet water temperature is regulated with 8 partialization steps.
Hydraulics • These are composed of the following macro components: • • Pump group: 1 or 1+1 (stand-by); • • Victaulic connections to the user (only if there is a pump group); • • Suction tap (one per pump); • • Water flow differential pressure switch (standard); • • Double cut off on the pumps (cut off tap on the valve inlet and check valve on the discharge, only with double pump group); • • Bleeding valves on the couplers (including hydraulic • pipe kit); • • Anti-freeze heaters (optional) on: • − Evaporator; • − Connecting pipes; • − Pumps.
Hydraulic circuit diagram • Check valve • Pump cut off tap • Pump • Discharge water temperature sensor • Evaporator • Differential pressure switch • Inlet water temperature sensor
General description of the unit • In BRA units, the inputs and outputs of the 2 circuits are divided on the two pCO1 board, connected together via a pLAN connection. • These two boards behave as a single microprocessor. • The control is composed of: • A pCO1 microprocessor control board when all of the devices are connected (sensors, probes, alarm instruments, relay, valves, etc.) (board n. 1) • A user interface
Main functions • These are the main functions offered by the control system: • Control of the water discharge temperature via a configurable set point • Possibility of setting a double set point • Automatic management of changes in the set point via the compensation function of the external temperature • Complete control of the compressors (timings, pump down, rotation, number of inrush currents) • 3 different types of condensation: steps, modulating, ulta low noise modulating • Management of the circulation pump, heat pump operation, and heating against the freezing of the components • 2 different password levels • Possibility of communicating by means of a RS485 supervision system • Possibility of setting the time and date by means of an optional clock card
Accessing the parameters : Consulatation & Programming READ ONLY: allows the parameters to be consulted without the possibility of modifying them. READING & PROGRAMMING: allows the data and parameters which are memorised in the microprocessor board to be modified. Press the button until an acoustic signal is heard Immediately press the buttons Insert the password required MEANING OF THE KEYS Allows the hour-counter to be reset and the hour thresholds to be modified for each component Allows the second level alarms to be configured Allows real configuration of the unit, delay setting, manual start-up of the units and their components Contains all the functions connected to the clock card Allows the set points to be modified Allows the remote control, the LAN and the serial settings to be configured
Changing the language Programme version It is possible to change the langauge at any time by using the user terminal. To change the language, press the following two buttons at the same time: By pressing the key it is possible to display the version of the programme installed in the Flash Eprom. This information is useful if it is necessary to add another unit to the LAN network LAN. In fact, in this case all of the units need to have the same programme programme installed on the microprocessor board.
Resetting the set point Optional clock card To carry out a reset of the factory set set points and other values (except those concerning hardware configuration), it is necessary to press the keys at the same time for at least 5 seconds. • If a clock card is installed in the microprocessor board, the date and time are shown on the status mask. • It is also possible to set: • Start-up and shut-down of the unit based on a time schedule • Alarm history memory
Hardware configuration 1/7 • These masks allow the type of unit to configured: • CHILLER STANDARD VERSION • CHILLER LOW TEMPERATURE VERSION • CHILLER HEAT RECOVERY VERSION • HEAT PUMP • HEAT PUMP WITH EHAT RECOVERY • CHILLER WITH FREE COOLING • The second and third masks allow the liquid injection or ECO options (optional) to be selected. • These masks allow the parameters concerning fan speed modulating regulation to be set according to the condensation pressure: by setting the low noise mode, regulation is carried out in three steps rather than two.
Hardware configuration2/7 By setting the low noise version, regulation is carried out on 3 steps, Rather than 2 which is standard. The following two graphs show the two different operating modes: Standard modulating regulation First ramp Modulating Regulation in low noise mode Prima rampa Second ramp
Hardware configuration3/7 Fan speed regulation ramp Fan cut off Condensation pressure Cut off differential Ramp differential
Hardware configuration4/7 Fan speed regulation ramp Fan cut off Cut off differential Ramp differential 1 Ramp differential 2
OFF ON External temperature 18 °C 20 °C Hardware configuration5/7 The directly connected fans (without speed regulation) are activated if the external temperature rises above 20 °C, or if the use of the compressors reaches 75% of its capacity. The K value is 70, and is necessary to make the fans reaction softer in relation to the action required within the proportional band.
Hardwareconfiguration6/7 These masks allow the reading range of the high and low pressure sensors to be set (ratiometric sensors). PROGRAMME SETUP: this is an operation which must always be carried out in the event of the unit programme being re-installed. It is useful if the data contained in the programme cause malfunctions. This operation resets all of the parameters, taking them back to the standard values. AL. PAGE CLEAR-UP: this option cancels the last 99 memorized alarms. HARDWARE SET-UP: enables an automatic reading of all of the parameters installed. It is not used for the clock card or RS485 card.
Hardware configuration7/7 • The directly connected fans are switched on when one of the following situations occurs: • Use of the compressors > 75% • External temperature > than a configurable value (standard 20°C) This is an optional function: as a default these units have a pressure transducer onboard, using therefore an additional NTC sensor, the subcooling value can be measured (considering the liquid after the condenser), in this way the unit can be checked to see if if is correctly loaded with gas.
Evaporator anti-freeze function with control on the discharge This function requires low pressure transducers. This advanced function checks for the presence of ice inside the evaporator, monitoring the delta between the evaporating pressure and the inlet water temeprature. When ice is present the circuit affected is immediately partialized generating a pre-alarm. If this situation is repeated 4 times within the space of one hour an anti-freeze alarm is generated which blocks both of the circuits (which requires intervention).
Conditions which trigger defrosting Phase 1 = the evaporating pressure of either circuit must reach the protection level. Phase 2 = the control immediately calculates at this evaporating pressure value and depending on the external air temperature read by the sensor, the unit capacity by fixing and memorizing the value at these conditions (ΔT = Text-Tevap. re-calculated by the system with a ΔT referring to a Text of 5°C) Phase 3 = If the evaporating pressure continues to remain below the protection level, the control continues to memorize and recalculate the capacity by comparing it to that previously fixed in order to establish the decrease in % over time. Phase 4 = When the decrease in capacity is lower than the value calculated by the control during stable operation, the defrost operation is activated and will take place only if the conditions remain for 180 seconds.
Defrost activation Once 180 seconds have passed the control will: • Invert the valves or the 4-way valves from heat pump to chiller • Turn off the compressors of the circuit not requested to carry out defrosting • Turn off the fans The request to end the defrost cycle and activate the compressor block occurs when the condensation pressure reaches 23 bar or if the defrost cycle reaches a maximum time of 5 minutes. DRIPPING CYCLE ACTIVATION: Phase 7 = Once the compressors have been turned off, the control will carry out several checks to evaluate the mode and length of the dripping cycle: 1st case = If the Text < than 5°C, compressors off for 120 seconds and fans switched off. 2nd case = If the Text > than 6°C, compressors off for 60 seconds, fans off for 30 second and then switched on at maximum speed for the remaining 30 seconds. END OF DEFROST AND RETURN TO NORMAL OPERATION: Phase 8 = At the end of the dripping cycle the control will: • Carry out an inversion of the valve or the 4-way valve from chiller to heat pump • Switch on the compressors
Unit remote control / LAN 1/2 Unit start-up is requested by a clean N.O. contact which is connected to the microprocessor board. This mask allows the selection of a start-up via external contact or by a supervision system. A supervision system exchanges information by means of a serial cable with the mother board of the unit which is remotely controlled. To enable this function a RS485 serial card is required. In the 4th line, if there is a LAN connection, it is possible to set the number of units connected in the LAN.
Unit remote control / LAN2/2 These masks refer to the parameters concerning automatic rotation between the units which are operating and the units in stand-by. This rotation, the cycle length (00 means rotation every 2 minutes), the number of units in stand-by (1 or 2) can be set. Rotation can be carried out on a timed basis or following a second level alarm. This mask is only shown if there is a LAN connection and it enables the unit to operate with an average temperature value, measured from all of the units. The other mode is Local, where the value measured is that obtained from only the sensor of that particular unit.
Delay settings 1/2 A start-up delay after a break in the power supply avoids the problem of multiple start-ups in various untis at the same time. In the units connected in LAN there is an automatic sequence of 5 seconds between one unit and another. The LP Stat Delay is the time during which the reading of the pressure switch is ignored. In this way the compressor can start up even at low temperatures. The Start Transient is the time after the start-up in which the regulation process will begin. This mask enables the anti hunting time constant to be set in order to avoid thermal variations which are too great. This value must be selected according to the thermal inertia of the site in which the unit is installed.
Delay settings 2/2 The first parameter is the delay after which the unit starts to read the signal isued by the water flow meter, while the second parameter is the delay of the alarm signal after pump start-up. • This mask enables the compressor timing to be set: • Minimum time between two start ups of the same compressor • Minimum operating time of each compressor • Minimum shut-down time of each compressor • Minimum time between two consecutive start-ups of different compressors
Set point 1/2 This mask does not allow any type of modification. It only shows the water set point which the unit takes into consideration for regulation. This mask allows the cooling set point to be set as well as a second set point which can be activated by means of a commutation of the contact connected to the digital input ID10. The hysterisis value is also shown. This value cannot be modified by the user, but is automatically managed by the control, which continously searches for the lowest value according to the dynamic characteristics and the thermal inertia of the system.
Set point 2/2 This mask enables the water inlet temperature threshold to be set. This mask enables the Set back Mode to be activated as well as the temperature value during this operating mode. If there is a second temperature sensor on the water tank, it is possible to select which sensor will provide the temperature value which needs to be maintained. COOLING ON REQUEST: unit start-up only with cold/hot water.
Free-cooling series 1/4 When the chiller is used to cool technologcial systems which operate in all seasons, the new BRAF and BRAM units posses a free-cooling function which can significantly reduce energy consumption. By using this system, when the external temeprature is low enough, it isn’t necessary to use the compressors of the chiller, in fact, these compressors are responsable for the majority of the energy consumption. In these units, the chilled water is produced by using the external air, in this case the only energy required is that used by the fans.
Free-cooling series 2/4 With this method, chilled water can be obtained without cost. AQUAFLAIR B.R.A.:these units offer the possibility of using free-cooling also when the external temperature of the external air is not low enough to ensure that the heat is completely removed. In this case, the operation mode is called “mixed”: the chiller uses the external air to pre-cool the refrigerant, allowing the compressors to work less, reducing therefore energy consumption. The three operating conditions can be summarised as shown in the following diagrams: • Free-cooling(fans and free-cooling pump operating); • Mixed(fans and free-cooling pump oeprating, compressors partially operating); • Mechanical cooling (direct expansion) (fans and compressors operating) • Freecooling, withT est < 5°C • Mixed, with 5°C < T est < 12 to 15°C • Mechanical cooling with T est > 12 to 15°C
Free-cooling coil Free-cooling pump Condensing coil Scroll compressor Evaporator Free-cooling series 3/4 The objective is for the chiller to produce chilled water by using external air instead of operating in direct expansion mode with mechanical cooling.
Free-cooling pump Free-cooling series 4/4 When the external air temperature is low enough, the microprocessing control system activates the free-cooling mode: the water is made to circulate through the free-cooling pump inside a special heat exchanger, and it is cooled by the external air issued by the fans, which, together with the pump, are the only components which absorb energy.
Anti-freeze device • Mangement of the anti-condensation heaters; •Management of the anti-freeze function of the evaporator (with pressure sensors); • Anti-freeze function during pump stand-by; • Intelligent defrost system, useful for minimising the number of cycle inversions.
Thermo-magnetic switches for the compressors pCO1 board connected in pLAN Thermostat Thermo-magnetic switches Contactors Compressor contactors Fan contactors Electrical board main components