VRV II Air Conditioning Guide Specification Cooling Only
PART 1 SYSTEM OBJECTIVES
1010 PERFORMANCE OBJECTIVESThe VRV plant is installed to maintain environmental conditions within the areas allocated to be Air Conditioned to the design parameters listed below.
1020 DESIGN PARAMETERS
Room Temperature 22°CWB ± 0.5°C (range between 16°C to 32°C)
Ambient Temperature (Summer) 35°C (max43°C to -5°C in cooling mode)
Ambient Temperature (Winter) -5°C (max15.5°C to -20°C in heating mode)
Room Noise Level NR38
External Noise Level 50dBA at 10m (RXYQ10MY1B 58dBA at 1m)
1030 GENERAL SYSTEM DESCRIPTION
The VRVII cooling only systems shall be installed to provide cooling to the areas via individually controlled room units on the same refrigeration circuit.
The outdoor equipment shall be an Air Cooled Modular Design Variable Refrigerant Volume (VRV) system as manufactured by Daikin.
The VRVII system shall be an Inverter Driven 2 Pipe system, which operates on energy efficient R410A refrigerant. See attached schedule for details of equipment selected.
Each system shall be based on one modular outdoor air cooled condensing unit connected via a single refrigerant circuit comprising suction and liquid pipe work for up to 16 indoor fan coil units, of different types and capacities. The total load of which should not exceed the total outdoor unit’s capability index, (see Daikin Data Book for capability index combinations).
The systems shall be capable of operating when ambient temperatures vary between 43°C and -5°C in cooling mode and between -20°C and 15.5°C in heating mode.
The internal temperature control range is between 16°C and 32°CWB.
The refrigerant pipe work circuit can be extended up to 150 metres actual (175m equivalent length) between the outdoor condensing unit and the furthest indoor unit on the circuit and may incorporate a 50 metres level difference without the necessity for any oil traps., also not to exceed 40metres from the first branch. The level difference between indoor units on one system can be extended to 15 metres.
Operation of the system shall permit cooling of each fan coil or all of the fan coil units serving a common room. Each fan coil or group of fan coils shall be able to provide set temperature independently via a local remote controller, an Intelligent Controller, an Intelligent Manager or a BMS interface. (E.g. Bacnet Gateway).
The system shall operate with Refrigerant HFC R410A (R32/R125 (50/50)), the installation to be in accordance with BS EN378: 2000 Parts 1-4 and Daikin’s design and installation instruction listed in the VRVII Installation Instructions, and Serviced in accordance with SiE39-302.
The units shall be manufactured and designed to standards relating to quality assurance under ISO9001, ISO9002 and ISO14001. Also be fully compliant with CE Regulations 1995 with respect to the following areas MSD89/392/EEC - Machine Safety Directive, LVD73/23/EEC - Low Voltage Directive, and EMC Directive EMV89/336/EEC - Electro-Magnetic Compatibility, and PED conformity.
1040 OUTDOOR UNITS
The outdoor units are to be:
Cooling Only type selected from the model range RXQ to suit the required capacity and future capacity, (RXQ5MY1B, RXQ8MY1B and RXQ10MY1B). See attached schedule for details of equipment selected.
The outdoor condensing units shall be completely weather proofed to corrosion resistant type E1. Factory assembled in a sturdy weatherproofed casing constructed from rust-proofed mild steel panels (Galbarian Steel) coated with an electro-painted oven baked enamel finish. Also pre-charged, pre-wired and completed with all necessary electronic and refrigerant controls for ease of installation and factory tested.
The outdoor units model 8 (23kW) and 10 (28kW) shall have a minimum of two compressors and able to operate even in case that one compressor is out of order. The model 5 (14.5kW) Model shall have a single scroll compressor.
Heat Exchanger
The heat exchanger on the condensing units shall be manufactured from Hi-X seamless copper tube with N-shape internal grooves mechanically bonded on to aluminum fins to an e-Pass Design. The fins are to be covered with an anti-corrosion Acrylic resin and hydrophilic film type E1. The pipe plates shall be treated with powdered polyester resin for corrosion prevention.
Compressor
The compressor shall be of the high-efficiency Hermetically Sealed Reluctance DC (Digital Commutator brushless motor) Scroll type employing neodymium magnets with gas fed directly to the compression process. The motor is cooled by pressurized gas and has no accumulator.
Each outdoor unit shall have at least one inverter driven compressor electronically controlled and capable of changing the speed linearly to follow the variations in cooling loads. In the cases of two or more compressors there shall be duty balancing. This shall be by the use of HIDECS circuit (Hi Inverter Drive and Electronics Control System) together with independent multi-variable PI (Proportional Integral) control for the precise monitoring of status of the system. With optimum capacity control of one or two standard drive compressors in accordance with load.
Capacity control of the outdoor unit shall be inverter controlled with 13 steps for model 5 and min of 20 steps for all other models, then with by-pass for minimum capacity control of 14% on model 5 and 8% on the other models. The frequency of inverter control shall be determined electronically by sensing ambient temperatures, operational pressures and monitoring the exact requirement of all of the connected indoor units.
Electronics
The outdoor electronic PCB’s shall be lead free and have selection switches for the length of pipe work, ambient range selection, emergency operation switches, and service mode switches, together with LED indications for the number of fan coils connected, the frequency status and operational/fault indication. The control circuit shall have a pump down facility to enable collection of the entire refrigerant charge in the system at the outdoor unit.
The units shall have microprocessor control system incorporated to enable oil return, stability of refrigerant flow and capacity balancing.
The following safety devices shall be part of the outdoor unit;
High and low pressure switches,
Control circuit fuses,
Crank case heaters,
Thermal protectors for compressor and fan motors,
Over current protection for inverter
Anti recycling timers.
The condensing units shall be capable of sequential start when more than one unit is installed and have an auto restart capability after power failure as standard.
Refrigeration Circuit
The refrigeration circuit of the outdoor unit shall include a SCe-Bridge Circuit complete with solenoid valves, 4 way valve(s), distribution headers, capillaries, filters, shut off valves, service ports and receivers.
Oil Recovery
The oil recovery cycle shall be automatic, occurring 1 hour after start of operation and then every 8 hours of operation. Oil separators are standard with the equipment together with oil equalization system between compressors.
Fan
The outdoor fan impeller shall be of aero spiral type, designed for low noise operation with manipulation on the fan blade edges to reduce turbulence and have a aero fitting discharge grill. The fan motor shall be DC (Digital Commutator brushless motor) inverter speed control to maintain constant head pressure control in all ambient conditions and modes of operation. Fan motors shall have external static pressure of 58Pa (6mm H2O). The outlet can be ducted using Daikin Air Discharge Duct (KPF26B160/280/450) provided air volumes are maintained.
Night set back control of the fan motor for low noise operation by way of limiting the maximum speed will be permitted.
1050 INDOOR UNITS
The basic components of the indoor units are a fan, a heat exchanger and an electronic proportional expansion valve which shall be controlled via computerized PID control which constantly, every 20 seconds measures and assesses the status of the return air temperature, refrigerant inlet and outlet temperature.
The indoor units shall be selected from the following types of Daikin units using R410A:-
Ceiling Mounted Cassette Type (Double Flow) FXCQ-M
Ceiling Mounted Cassette Type (Multi Flow) 600 x 600 FXZQ-M
Ceiling Mounted Cassette Type (Multi Flow) FXFQ-M
Ceiling Mounted Cassette Corner Type FXKQ-M
Ceiling Mounted Built-In Type FXSQ-M
Ceiling Mounted Built-In Type (Small) FXDQ-M
Ceiling Mounted Duct Type FXMQ-M
Ceiling Suspended Type FXHQ-M
Wall Mounted Type FXAQ-M
Floor Standing Type FXLQ-M
Concealed Floor Standing Type FXNQ-M
See attached schedule for details of equipment selected.
During the cooling operation the electronic expansion valve shall control the degree of refrigerant superheat at the evaporator outlet. During the heating operation it shall control the degree of refrigerant sub cooling at the condenser outlet.
The indoor unit printed circuit board shall be complete with power input fusing, address switches for a variety of operation controls, emergency operation switch and fault/operation indication LED's. Fan motors shall be thermally protected.
The indoor unit casing of ceiling concealed and cassette types, shall be fully insulated and sealed to prevent condensation. The insulation shall conform to BS476 Part 7 fire rating.
1060 LOCAL SYSTEM CONTROLS
The controls system shall include all necessary Daikin remote controllers and interface PCB's.
One remote controller (BRC1D51) shall be provided per room or fan coil as specified and be capable of controlling an individual fan coil or group of fan coils, up to 16 indoor units.
The controller shall have a liquid crystal display and provide the following facilities:
Temperature setting
Fan speed setting
Mode setting fan/cooling
On/Off control
Diagnostics Feedback
7 Day Timer Function
Remote air sensors KRCS01-1 shall be provided for local room sensing where fresh air is introduced to the fan coil unit. To be positioned within the room or close to the return air grill in the ceiling.
1070 BUILDING MANAGEMENT SYSTEM
Intelligent Touch Controller DCS601B51All the air conditioning systems shall be controlled by an intelligent Touch Controller system with full colour LCD touch panel and Icon display as manufactured by Daikin, optional with Power Proportional Distribution Function (PPD) for individual billing. With the following functions;
Automatic cooling/heating changeover
Heating optimization
Temperature limit
Yearly schedule
Power Proportional Distribution (optional)
Fire emergency stop control
Flexible timer functionality (several schedules up to a full year)
Flexible grouping in zones
Historical data
Password security levels
Connectable to Daikin Sky Air & Splits via an interface adapter
Operation of up to 64 groups of indoor units (with maximum 128 indoor units)
Intelligent Manager DAM602A51/52/53All the air conditioning systems shall be controlled by an Intelligent Manager system as manufactured by Daikin that shall be controlled via a PC recommended by Daikin, with optional Power Proportional Distribution Function (PPD) for individual billing. With the following functions;
Monitoring
Control, Operation and Setting
Display
Yearly schedule
Measurements
Management
Data Storage and Reports
Emergency stop control
Password security levels
Power Proportional Distribution (optional)
Operation of up to 1,024 indoor units
BACnet Gateway DMS502A51Interface unit to allow communications between VRV and BMS’s. BMS ready to run and monitor the air conditioning systems through BACnet communications.LONWORKS Gateway DMS504B51
Interface unit to allow communications between VRV and BMS’s. BMS ready to run that can be controlled via a personnel computer
and monitor the air conditioning systems through LONWORKS communications.
1080 REFRIGERATION PIPEWORK
Supply, install, test and commission all interconnecting refrigeration pipe work between the outdoor unit and the connected indoor units.
The pipe work installation, charging, testing and commissioning shall be carried out by REFCOM registered refrigeration engineers, who shall be fully trained in the safe handling of refrigerants and CITB trained in brazing techniques.
The installation shall be fully in accordance with British Standard BS EN378: 2000 Parts2-3 and Daikin’s design and installation instructions listed in the VRVII Installation Instructions.
All pipe work installations shall be carried out in refrigerant quality soft or half hard drawn copper tubing to BS2871 Part 2: 1972 and complete with the appropriate Refnet headers and Refnet joints (as manufactured and supplied by Daikin).
Longest possible lengths of copper pipe shall be utilized to minimize the number of joints on site; appropriate refrigeration installation tools must be utilized to avoid the use of elbows. Oxygen free dry Nitrogen (OFN) must be in the system during brazing (no cold brazing is allowed).
Pipe work shall be properly and neatly fixed and supported at a minimum of 2 metre intervals and where possible should be run on galvanised cable tray. All pipe work to be tagged with ID number (Condensing Unit ref) at 3 metre intervals.
Pipe supports shall not restrict expansion or contraction of the pipe and restraint must not be applied to Refnet joints or Headers.
All pipe work (suction and liquid) to be insulated with slip on close cell electrometric pipe insulation (as manufactured by Armaflex or equal and approved), fire rated to Class "O" Building Regulations 1985, with a wall thickness of not less than 13mm. Insulation must be protected when exposed to atmosphere by special paint or covered by an enclosure.
All joints, after pressure and leak testing, are to be properly glued and or taped as to provide a complete seal to prevent any condensation, and shall be clearly marked for ease of identification.
After installation of pipe work, prior to connection to the condensing units, sealing of insulation joints and starting of equipment, pipe work should be pressure tested using oxygen free dry nitrogen as out lined below to 38 Bar (551 Psi), held for 24 hours and checked for leaks.
Step 1
Pressurize to 10.3 Bar (149 Psi)
3 minutes or longer
Allows discovery of major leaks
Step 2
Pressurize to 21.5 Bar (312 Psi)
5 minutes or longer
Step 3
Pressurize to 38 Bar (551 Psi)
Approx 24 HOURS minimum
Allows discovery of minor leaks
Condensing units shall be connected using a torque wrench to tighten to the correct specified toque (see table below) where appropriate.
Flare Nut Size
Standard Tightening Torque
Kgf.cm
N.cm
1/4
144~176
1420~1720
3/8
333~407
3270~3990
1/2
504~616
4950~6030
5/8
630~770
6180~7540
3/4
990~1210
9270~11860
The system shall then be vacuumed/dehydrated to 0.2 torr (-755mmHg) and held at that setting for 1 hour (minimum) to 4 hours depending on pipe length using a 2-stage vacuum pump.. All of the above works shall be carried out before electrical connection is made to the fan coil units.
The additional refrigerant (HFC R410A) charge shall be calculated and weighed to accommodate the actual installed and measured length of pipe work all in accordance to Daikin recommendations and instructions listed in the VRVII Installation Instructions.
The charging should be carried out with an appropriate charging station in the liquid phase and under supervision.
1090 CONTROL WIRING
All control wiring is to be carried out in 2 core 0.75mm2 - 1.25mm2 PVC non screened CY flexible control cabling to BS6141 and BS6500 (To comply with CE Regulations 1995) colour coded and separately marked at 3 metre intervals for ease of identification and maintenance.
1100 INSTALLATION
The installation company shall be Approved Daikin Installers, whose installation engineers shall have attended the relevant Daikin equipment courses. Proof of compliance may be requested before commencing works. Approval is given by a Daikin Distributor. The tendering contractor must state on his tender return submission the name of the specialist Daikin approved sub-contractor to be employed to carry out the VRVII installation.
The installation of all internal and external units, refrigerant pipe work, inter-connecting wiring, testing shall be carried out by the above stated approved Daikin Installer.
The approved Daikin specialist refrigeration installer or/and a Daikin Distributor’s representative shall carry out/or witness the commissioning of the VRVII system and final inspection and record data as listed below;
Record Pressure Test (Holding Pressure)
Confirmation of Record Drawings
Record Pipe Lengths
Record Pipe Diameters
Additional And Total refrigerate Volumes
Addressing of Fan Coils
Cooling Start Up Check
Complete and issue Documents and Certificates to Consultant/Client.
Should it be deemed necessary full access should be afforded to the site during the installation of the VRVII to allow a Daikin Distributor’s representative/engineer to verify that the installation methods being used comply and are fully in accordance with the Daikin VRVII Installation Instructions, requirement in order that the equipment warranties will not be invalidated.
A list of nominated Approved Daikin Installers is available from the Daikin Distributors.
1100 EQUIPMENT MAINTENANACE & WARRANTY
The sub-contractor shall supply all the specified equipment complete with one year’s warranty on both materials and labour commencing on satisfactory hand-over of the complete system.
The sub-contractor shall include for a one-year maintenance contract on the complete installation, with guaranteed maximum 24-hour response time. The sub-contractor shall ensure that the warranty and maintenance contract he provides is underwritten by a Daikin Distributor, and shall provide to the employer documentary evidence of the same.
The maintenance contract, which must be in place within three months of project completion, shall include for all works necessary to ensure that the three year equipment warranty given by Daikin is not invalidated, and shall provide documentary evidence to this effect.
1120 REFRIGERANT LEAK DETECTION
The sub-contractor shall supply and install a Daikin Refrigerant Containment (Leak Detection) System (KFLD26B / KHLD26A) as indicated BS EN378 to provide a comprehensive coverage for any potential leaks. Should there be a leak; the system will raise an alarm at the building management system if supplied.
1130 CONDENSATE DRAINAGE
The sub-contractor shall supply and install a condensate drainage system to convey condense waste from each fan coil unit. The system shall be installed with all necessary pumps and fixings to adequately drain to the rainwater system.
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