Air Cooled Packaged Systems AIRAH Back to Basics

Transcription

1 Air Cooled Packaged Systems AIRAH Back to Basics

2 What s changed? New Refrigerants R410a MEPS EER / AEER / SEER Manufacturing Technologies Research, Development and Testing New technologies, controls, reliability Energy Modelling Energy Costs What is life cycle is it driven by corrosion, a compressor failure, time or Energy consumption

3 Manufacturing Technologies Exact refrigeration engineering science: Sound engineering, optimum balance points, specifically designed and circuited evaporator and condenser coils, selecting components at the correct duty points and correct refrigeration distribution and velocity. Raw materials go in one end of the building a fully formed air conditioner comes out the other. Volume assembly lines has ensured lower costs and internationally competitive pricing. Components are well known and very reliable brands Air Cooled Packaged Units AIRAH Back to Basics 3

4 Research & Development Air Conditioning Manufacturing Engineers are specialists in refrigeration engineering science focused on the design of balanced integrated systems of a package or a split. Product/industry expertise - we understanding local climates and conditions we design our products to excel in these conditions. Testing rooms insure compliance to MEPS Test room controllable temperature range - 15C to +60C Anechoic chamber for sound level testing Fan testing chamber Calorimeter room for capacity testing MEPS or Just R&D Air Cooled Packaged Units AIRAH Back to Basics 4

5 What has not changed? Heat transfer Refrigeration cycle It s too hot or it s too cold I need it now How does that work? This is not working?

6 The system has been the same since 1834 We just know how to control and balance it better now Air Cooled Packaged Units AIRAH Back to Basics 6

7 How the humble old packaged machine has changed 10 years ago Today Cooling Capacity 50.3 Cooling Capacity % Power Input 24.9 Power Input % EER 2.01 EER % Air Cooled Packaged Units AIRAH Back to Basics 7

8 Technologies changing the face of refrigeration Latest technology in variable compressor control Digi, VRF Electronic Expansion Valves (EEV) - Superior refrigeration system balance and control under all load conditions EC Motor Plug Fans - EC Fan capabilities for system performance and part load performance Latest in Self Diagnostics and BMS interface capabilities Latest in coil design technologies Air Cooled Packaged Units AIRAH Back to Basics 8

9 Digital and variable compressor technologies We must understand the differences between the inverter compressor and the digital compressor and NOT get confused with trying to compare a Digital compressor in a package unit to a VRF system VRF system uses an inverter compressor, uses varied refrigerant mass flow, uses EC motors and variable air flow which all contribute to the VRF efficiency, where as a package system with a digital compressor uses the digital compressor for load and or capacity control with no refrigerant mass flow actual reduction is the pulsating on/off unload / loaded state, nor is there a use of EC motors or variable air flow. Both are very different technologies and before we can talk about benefits of one over the other these questions need to be asked. What s the application, part load opportunities, comfort, process etc Is there part load opportunity or will the machine run at full load all the time What is the load sensible or latent What is the cooling profile Air Cooled Packaged Units AIRAH Back to Basics 9

10 Variable Compressor Inverter compressor: uses an external variable frequency drive - to control the speed of compressor. The refrigerant flow rate is varied by the change in the speed of compressor. The turndown ratio depends on the system configuration and manufacturer. It modulates from 10% up to 115% at full capacity with a single inverter. (can differ from manufacturer) The variable frequency drive controls the speed of compressor motor. The compressor is specifically designed to run at different motor speeds to modulate cooling output.variable speed operation requires an appropriate compressor for full speed operation and a special compressor lubrication system. Proper oil management is a critical requirement to ensure compressor lifetime. Proper oil management provides proper lubrication for scroll set at low speed and prevents excess oil from being injected into the circuit when operating at full speed. Air Cooled Packaged Units AIRAH Back to Basics 10

11 Variable Compressor - Digital This technology is inherent in its simplicity. The standard Copeland Scroll has a unique feature called axial compliance. This allows the fixed Scroll to move in the axial direction, by very small amounts, to ensure that the fixed and orbiting scrolls are always loaded together with the optimal force. This optimal force holding the 2 scrolls together at all operating conditions ensure the high efficiency of Copeland scrolls. The Digital Scroll operation builds on this principle. The Digital Scroll operates in two stages - the "loaded state", when the solenoid valve is normally closed and "unloaded state", when the solenoid valve is open. During the loaded state the compressor operates like a standard Scroll and delivers full capacity and mass flow. However, during the unloaded state, there is no capacity and no mass flow through the compressor. If you look at actual data of a machine and just look at the EER of it with a digital compressor, remember as the compressor unloads the amps drop and the suction pressure increases so the gains when unloaded are reduced running amps. The digital compressor in isolation is a capacity modulation device not an energy efficiency device, however when used in a well controlled machine with an EC evaporator plug fan, electronic expansion valves and or Economy cycle all controlled and system balanced significant efficiency gains can be realised. Air Cooled Packaged Units AIRAH Back to Basics 11

12 Variable Capacity Compressor Digital Scroll Compressor Benefits 10% - 100% wide capacity modulation Fast cooling and heating Higher part load efficiency due to matching room heat load Precise temperature control with improved comfort Better humidity control as constant coil temperature No oil return issue Simple electronics, no EMI issues Easy to install, service and maintain Air Cooled Packaged Units AIRAH Back to Basics 12

13 Digital Compressor Efficiency Air Cooled Packaged Units AIRAH Back to Basics 13

14 Control

15 Close Comfort Control Controllability allows close control air supply giving your space superior comfort Air Cooled Packaged Units AIRAH Back to Basics 15

16 Unit Control With variable compressor technology, EEV, EC fan technologies and economy cycle all being controlled and monitored by the unit controller, makes for energy optimisation for both heating and cooling. The unit controller, is the key to your systems energy efficiency. It s responsible for: control balance safety optimum plant efficiency continually monitoring and adjusting system performance, with changing outdoor temperatures. Air Cooled Packaged Units AIRAH Back to Basics 16

17 Technology Gains Versus Costs Air Cooled Packaged Units AIRAH Back to Basics 17

18 Efficiency

19 Energy & Cost Saving Features Variable capacity compressors Digital and Inverter EC Motors Economy cycle EC Plug Fans EEV for optimised refrigerant flow How we control / balance the system Air Cooled Packaged Units AIRAH Back to Basics 19

20 Economy Cycle The Economy Cycle presents significant energy savings by utilising outside ambient air to cool the space. When the outside ambient air is below the set point required, the compressor is cycled off, outside air dampers open, and the supply air fan continues to run, bringing cool air in from outside. The main benefits: Reduced power consumption Reduced compressor run hours Requires the installation of motorized dampers & corresponding controls that can monitor outside air temperature. Air Cooled Packaged Units AIRAH Back to Basics 20

21 EC Motors & Plug Fans EC Plug Fans offer many benefits when applied to Packaged Air Conditioners High Efficiency of 90-95% = Lower Input Power Lower air temperature rise in airstream Infinite Fan Speed Control Increased static pressure limits - Plug Fan Longer motor life resulting from lower running temperatures Longer bearing life due to soft start feature Suitable for 240V supply Quiet operation slow ramp up Air Cooled Packaged Units AIRAH Back to Basics 21

22 EC Fan Efficiency EC vs AC - Power Input to Fans Fan size: ebmpapst A3G800 Air Cooled Packaged Units AIRAH Back to Basics

23 EC Motor & Plug Fans Plug fan option alone gives you a 12% EER increase Air Cooled Packaged Units AIRAH Back to Basics 23

24 Electronic Expansion Valves EEV s provide more efficient control of the refrigerant flow, and also reduce the condensing pressure in the system Air Cooled Packaged Units AIRAH Back to Basics 24

25 Electronic Expansion Valves Low condensing pressure High cooling capacity High efficiency Refrigeration Balance Air Cooled Packaged Units AIRAH Back to Basics 25

26 Variable and Fixed Expansion Air Cooled Packaged Units AIRAH Back to Basics 26

27 y Energy savings Discover up to 50% annual energy savings with latest technologies Air Cooled Packaged Units AIRAH Back to Basics 27

28 Running cost savings with new technologies and control Based on: Hours of operation: 4745 hours per year (8am to 9pm, 365 days per year) Occupancy: variable to simultaneous peak of 580 persons Peak cooling load 124kWr GTH/84.6kWr GTSH, (ACADS CAMEL ) Plant configuration 3 x 55kWr Rooftop PAC units Energy calculations using ACADS BEAVER Air Cooled Packaged Units AIRAH Back to Basics 28

29 Year round Plant considerations Summer - Peak cooling load Large Coils cope with a hot summer EC condenser fans lowering running costs Dry Mode providing humidity control Winter - Peak heating load Large Coils providing low ambient heating Inverter compressors and EC condenser fans provide efficient heating Spring / Autumn - Shoulder Dry Mode providing humidity control Part load efficiencies Digital / Inverter compressors 0 Plug fans Electronic valves Economy Cycle Air Cooled Packaged Units AIRAH Back to Basics 29

30 Refrigeration Guide Lines

31 Packaged Systems Single or Split Nominal Conditions: 27/19 C / 35 C ambient R410a SHR between 0.8 and 0.85 SH between 3-5 K Target SC 3 to 5 K Target DSH 25 K Target SST 5 and 13 C (vary with balance) SCT C (+60) HP Trip 4200 KPa DT C ( C) Evap TD C at.8 to.85 SHR Evap TD 6-8 C at.5 to.75 SHR Cond TD C target Evap Abs. Press 1060 kpa Cond Abs. Pressure 3400 kpa Air Cooled Packaged Units AIRAH Back to Basics 31

32 Where has HGBP gone?

33 Technology is the new HGBP Hot gas bypass was recommended when the load on an evaporator varies and operation of the air conditioning system is desired at lower than design conditions. Hot gas bypass provides an artificial load on the evaporator by introducing a portion of high pressure, high temperature gas to the evaporator / suction side of the system. In the past we use HGBP for high % outside air, variable air flow systems, coil velocities below 1.5 M/S or (30-35 L/S per KW), modulating periods of load, cooling below 20 C ambient. HGBP set to open at +1-2C and close at 4-5 C coil temperature NOW WHAT S CHANGED TECHNOLOGY HAS Variable compressors Digital / VRF Electronic Expansion Valves Variable Speed Fans Evaporator EC type Head pressure control condenser fans R410a and MEPS brought about new and efficient coil designs All controlled by the machines to ensure part load, superheat is maintained under all conditions 3-5 K, discharge superheat is maintained 20K, modulating and controlling all these new technologies to deliver close temperature control, conditions, system stability, balance and machine safety.

34 How external conditions change the operating system

35 90 KW Machine Supply air flow & wet bulb effect SAQ L/S EAT C TC KW SHR SST C E-TD DB C EVAP ABS PRESS kpa SCT C C-TD C THR KW AMB / / / / Air Cooled Packaged Units AIRAH Back to Basics 35

36 Air Flow & WB Effect SAQ L/S EAT C TC KW SHR SST C E-TD DB C EVAP ABS PRESS kpa Air flow drives SHR / Capacity 12.4 KW SCT C C-TD C THR KW AMB / Entering Coil Wet Bulb Drives / SHR / Air Cooled Packaged Units AIRAH Back to Basics 36

37 Ambient Effect SAQ L/S EAT C TC KW Ambient Drives Ref SHReffect SST 35 C = 90 KW C 20 C = 102 KW E-TD DB C EVAP ABS PRESS kpa SCT C C-TD C THR KW AMB / / / / Air Cooled Packaged Units AIRAH Back to Basics 37

38 14 Evap Temp V Nominal Air Volume - Fixed Speed Compressor E V A P T E M P c % 40% 50% 60% 70% 80% 90% 100% 110% 120% % Supply Air Fan

39 E V A P T E M P C Evap Temp V Variable Air Volume Digital Compressor 20% 30% 40% 50% 60% 70% 80% 90% 100% % Supply Air Fan Digital scroll lowers refrigerant flow rate, producing a higher evaporator temperature

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41 Piping Splits

42 Piping Systems Use Clean and sealed refrigeration grade pipe Cut only with pipe cutter Use long radius elbows (reduce PD) Use nitrogen when welding / testing Oil traps typically 8 m (refer manufacturers data) Insulation both is now recommended Evacuate min 500 microns 15 mins (smaller systems 90KW) Refrigerant charge SH 3-5 K when (21-27 C indoor / 24-35C amb.) Pipe sizes typically recommended by manufacturer Oil only added on extended pipe runs refer manufacturer Typically rotary compressors PVE Typically Scroll compressors POE R410a not mineral oil Crankcase heaters all compressors over 8 m pipe Refrigerant typically base charge (10M) and add grams /m past Typically above 60 M extra suction accumulator is required Line loss 6 to 8 % between 13 and 19 mm suction line Suction Line bend 16 MM = 0.30M / 19 mm = 0.45M Air Cooled Packaged Units AIRAH Back to Basics 42

43 R22 R410a

44 R22-R410a Repair, Replace??? Repair or replace: Questions to make the right decision AIRAH Life span recommendations AIRAH hand book Internal environment impacts on life span hours of operation External environment geographical location, ocean, desert Economical environment is the machine being maintained Availability of parts ROI return on investment can cost thousands of Dollars to replace a compressor when a new machine may cost 3 times this to purchase but have a EER 40% improvement The right advice to get the balance right cost V age / lifespan Many service companies now employ a predicted service schedule where history shows that this machine has a failure every 6 months so they schedule maintenance for every 5 months ---- Costs V predicted failure Refrigerant issues / GWP / ODP Do you replace like for like or ---- Air V Water Technical advice to make the right decision Air Cooled Packaged Units AIRAH Back to Basics 44

45 Applications Warehouses Shopping Centres Retail Bulk Storage Temperature controlled warehousing Pharmaceuticals etc. Supermarkets Conference Centres Community Buildings Data Centres Switch rooms Aquatic / Sports centres Schools Cinemas Museums Commercial offices Air Cooled Packaged Units AIRAH Back to Basics 45

46 Application Matrix Option Application Digi Comp EEV EC Plug Evap HPC High Sensible X X X High Latent X X X X EC Cond Fans Economy Cycle Dry Mode Reheat High Ambient X X X X X X Low Ambient Cooling X X X X X X HLI Stock STD Low Ambient Heating X X X X X Dehum Load X X X X X X X X Hot Start Efficiency X X X X X X X X X X X X Comfort Cooling X X

47 Thank you