EcoMesh Precooling System Reduce ru running cos osts an and ri - - PowerPoint PPT Presentation
EcoMesh Precooling System Reduce ru running cos osts an and ri risk of of HV HVAC C fail ailure du during hot hot wea eather 1 HVAC normal operating conditions 2 Hot weather events cause HVAC failures 3 HVAC industry response 4
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1 HVAC normal operating conditions 2 Hot weather events cause HVAC failures 3 HVAC industry response 4 Improve coil operating conditions 5 EcoMesh Precooling System 6 EcoMesh Case Studies 7 Planning an EcoMesh installation 8 Comparison with other precooling methods 9 Additional inner mesh for Transverse coils 10 Maintenance Requirements
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Air cooled condensers remove the heat from inside the building and reject it to the outdoors.
temperature rarely goes above 40°C)
Chillers and refrigeration units operate best when: HVAC systems are designed to provide cooling capacity for normal operating conditions. When sized correctly, HVAC systems perform well in all weather conditions.
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Typical example for a Carrier 30GK245 12 fan chiller with 725 kW nominal cooling capacity.
Carrier 30GK245 12 fan chiller with nominal capacity 725 kW cooling, Carrier 30GK245 - with 12 fans Chiller pumps chilled water into building … LWT (Leaving Water Temperature) set at a nominal 7 °C
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LWT - leaving water temperature at a nominal setting of 7 °C Each degree rise in ambient temperature reduces cooling capacity and increases power demand.
Typical cooling capacities - table
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At 30C 265kW At 36C 282kW At 40C 292 kW At 33C 273kW At 27C 256kW At 43C 299 kW
kW Air-on condenser Cooling Capacity Compressor Input power
Cooling capacity reduction between 30C and 45C: Cooling capacity reduces … 773 to 629 kW (-19%) Compressor load increases … 265 to 304 kW (+15%) COP reduces … 2.92 to 2.07 (-29%) Each degree rise in ambient temperature reduces cooling capacity and increases power demand.
HVAC problems are revealed when building load exceeds cooling capacity
Typical cooling capacities - graphed
6 Prison cell evacuation Hospital evacuation Deserted shops Unproductive staff Data centre shutdown And power bill shock
Every summer, hot weather event cause HVAC failure and expensive consequences!
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Most Australian cities experience hot weather events of 35°C or over … summer is the HVAC industry’s busiest season!! Canberra - maximum temperature days 18 30-34 35-40 40+ "hot days" Nov-16 6 Dec-16 16 Jan-17 13 12 12 Feb-17 8 4 2 6 Maitland - maximum temperature days 32 30-34 35-40 40+ "hot days" Nov-16 8 4 4 Dec-16 12 6 1 7 Jan-17 6 6 6 12 Feb-17 10 4 5 9 Wagga - maximum temperature days 28 30-34 35-40 40+ "hot days" Nov-16 9 1 1 Dec-16 19 4 4 Jan-17 11 13 3 16 Feb-17 13 5 2 7 Dubbo - maximum temperature days 49 30-34 35-40 40+ "hot days" Nov-16 14 2 2 Dec-16 15 12 12 Jan-17 11 13 6 19 Feb-17 9 8 8 16 Sydney - maximum temperature days 22 30-34 35-40 40+ "hot days" Nov-16 4 3 3 Dec-16 9 4 4 Jan-17 5 8 3 11 Feb-17 6 1 3 4 Melbourne - maximum temperature days 9 30-34 35-39 40+ "hot days" Nov-16 2 1 1 Dec-16 7 1 1 Jan-17 4 4 4 Feb-17 4 3 3
Source: BOM data for 2016/17
8 Older HVAC plant - condenser can’t cope and trip out above 35 C Building load creep - the condensers no longer sized correctly for the load Post installation building modifications
Hot roof scenario - the roof top is actually 5-10C hotter than the design condition Peak power demand may cause load shedding of individual units
Main reasons for HVAC failure:
Incorrectly configured HVAC plant
9 But if the system is unmodified, the next hot weather event will require additional call outs … sometimes multiple times in day or even weeks
Option 3: Replace the units half way through their service life … Option 2: HVAC Optimisation to improve HVAC performance: eg
Option 1: Emergency call out by technicians to reset the system …
But if condensers cannot reject sufficient heat, then any adjustments would be futile. An expensive and inconvenient scenario!
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30-50% of a building’s electricity demand is for refrigeration or air conditioning. Referring to the cooling capacities chart … A simple method to improve efficiency is to improve coil operating conditions by lowering the air-on coil temperature … Give the coils a “cool change” during hot weather events!! Efficiency gains in the HVAC system will reduce the building’s energy cost … especially during hot weather events. A lower air-on temperature, increases cooling capacity and reduces input power ...
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Pre-cooling the air on coils flattens the performance curves during hot weather. The unit operates in an environment where the temperature never rises above 35C. Overall effect is to lighten the refrigeration cycle and prolong the life of the HVAC plant.
kW Air-on condenser Cooling Capacity increases Compressor Input power decreases Typical performance curves with precooling.
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Mr Zafer Ure has nearly 30 years of engineering experiences as a consultant, senior design engineer and Sales Manager for PCM Products Ltd and EcoMesh Ltd. EcoMesh owner, Mr Zafer Ure.
Extract from published paper, 12th International Congress on Sustainable Energy Technologies, 26-29th August 2013, Hong Kong
EcoMesh introduced into Australia in 2014 but has over 20 years in Europe, India and the Middle East!
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Source: www.ecomesh.eu
Heatcraft Europe: Adiabatic solution by EcoMesh - panels and sprayers Trane Europe: Adiabatic solution by EcoMesh kits and controller
EcoMesh also the adiabatic solution for Heatcraft and Trane in Europe
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York YVAA Fujitsu Sydney Emicon RAE Data Centre Adelaide Carrier Aquasnap Netley Police Station Adelaide Trane ECGAM Ballarat Hospital York YLAA Port Pirie Hospital Temperzone OPA410 City X Adelaide York YLCA Queen Elizabeth Hospital
EcoMesh in Australia - since 2014
Carrier 30RB St Kilda Town Hall, Melbourne C Space building Canberra
EcoMesh precooling process
15 Water sprayers wet the inside of the mesh for a few seconds every 30 secs Mesh panels are installed outside the condenser coils. Water evaporates off the mesh to cool the incoming air.
EcoMesh has a patented coarse outer net (for structural support) and a fine inner mesh (for capturing water drops).
Temperatures above 30C
during summer months. “Adiabatic cooling” improves system COP and minimises risk of head pressure trips in summer. Mesh panels also protect the coil from solar radiation, hail stones and other air borne debris Air flows freely through and around the mesh panels. For most of the year, mesh in front of coils has a negligible impact on the chiller fan load.
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Estimated cooling efficiency
Mesh cooling occurs when water evaporates outside the coil. Mesh efficiency is based on the Delta-T or wet bulb depression
Best results are achieved when maximum wetted mesh is placed in the air stream entering the coils. Water use is minimal - sprayers increase spray time with each temperature increment. Mesh cooling efficiency can vary from 25-50% of the Delta-T.
Adelaide Kent Town Days Avg Delta T Mesh Days Avg Delta T Mesh 35-39 RH at 37 C effect 40+ RH at 42 C effect Nov-16 2 15% 18 C 6 C N/A N/A N/A Dec-16 5 16% 18 C 6 C 1 15% 20 C 7 C Jan-17 6 21% 16 C 5 C 2 12% 21 C 7 C Feb-17 2 14% 18 C 6 C 3 30% 15 C 5 C Mar-17 4 19% 16 C 5 C N/A N/A N/A
Estimated mesh cooling: At 30 C (RH 30%) approx. 2 - 6 °C At 35 C (RH 20%) approx. 4 - 8 °C At 40 C (RH 15%) approx. 6 - 10 °C At 45 C (RH 10%) approx. 8 - 12 °C
Water drops on inner mesh change state to vapour and cool air by latent heat of evaporation
Factors affecting mesh efficiency: ➢ Ambient temperature and relative humidity ➢ Coil design (standard vertical coil, V coil, W coil, Transverse V ➢ Placement of wetted mesh outside coils ➢ Spraying cycle and volume of water used Sites in hotter and dryer cities will run mesh more often and achieve the greatest benefit. For example, Adelaide experienced 25 hot days
For a mesh efficiency of 33%, see below estimated cooling for an Adelaide summer (Source: BOM data for Adelaide Kent Town)
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Case study 1: Small packaged unit, Temperzone OPA410
Ambient check 4.04PM: 43.2 °C Result: Mesh cooling down to 34.7 °C at 4.06 PM
The refrigeration service company installed EcoMesh and although a less efficient solution, EcoMesh prevented further nuisance trips. Estimated cooling efficiency:
➢ BOM data at 3PM was 41.2 °C & RH of 24% ➢ Ambient on roof was 43.2 °C and with 24% RH, this implies a Delta T of 17.4 °C ➢ Central mesh cooled from 43.2 to 34.7 °C or approx. 8.5 °C. ➢ Allowing for 30% losses at mesh open ends, average cooling across the entire coil is around 5 °C ➢ Estimated cooling efficiency for this site is approx. 29%. EcoMesh solution: Single panel across coil Temperzone unit was located on City X arcade roof in Adelaide city and regularly tripped
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Case study 1: Video of typical cooling
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Case study 2: Medium chiller, Emicon 8 fan
Two chillers located in a Pooraka data centre. Hot weather events necessitated direct spraying
Direct spraying can damage the coils so an engineered solution was required. EcoMesh was installed in early 2016. EcoMesh solution: 4 x EcoMesh panels across front and rear of chiller cabinet Four water headers, each with quad sprayers wet the inside of the mesh
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Case Study 2, Test 1: Temperature probe to measure cooling at the outer coils (Mar 1st 2016)
0:08 Ambient 32.2 0:16 Sprayers activated (3 sec spray) 0:25 Probe positioned near coils 32.1C 0:43 Temp of 29.3 (2.9 C cooler) 1:13 Temp of 28.9 - mesh still cooling just before next spray cycle at 1:16 Results: The mesh on outer edge of coils cooled the incoming air by about 3 degrees. For a Delta T
was approx. 20%
Ambient conditions on the day ➢ BOM data at 3PM was 32.2 °C & RH of 18 ➢ Ambient on roof was 32.2 °C and with 18% RH, this implies a Delta T of 15 °C The ambient temperature was recorded as 32.2 C at 3:17 PM. The sprayers were activated to wet the mesh for a few seconds, then probe readings were recorded as an MP4 file. Screen shots from the video below show cooling progress.
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Case Study 2, Test 1: Typical cooling measured on a 32 C day
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Case Study 2, Test 2: Use temperature loggers to record cooling at the inner coils (Mar 1st 2016).
Temperature logger results: Results: The inner coils were cooled by 9 C. For a Delta T of 15 C, cooling efficiency at the inner coils is around 60%. Allowing for 20% losses around the edge, this suggests a total cooling efficiency of approx. 45%.
Ambient drop due to humidification Upper and lower coil probes Max cooling 23.5C Start ambient 32.5 C
To avoid false “wet bulb” readings, the loggers were placed inside plastic bottles. Three probes were used: one for ambient and two for the upper and lower part of the coil. The sprayers were activated and the probes recorded temperature over 30 minutes. Ambient conditions on the day ➢ BOM data at 3PM was 32.2 °C & RH of 18 ➢ Ambient on roof was 32.2 °C and with 18% RH, this implies a Delta T of 15 °C
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Case Study 2, Test 3: Temperature probe to measure cooling at the coil behind an inner mesh (Mar 17th, 2016)
Probe in conduit At 4:35 PM Ambient 31.2 At 4:36 Air temp dropped to 29C Results: The inner coils were cooled by 6.9 C. For a Delta T
estimated to be 58%. This is similar to the 60% efficiency results achieved with the temperature loggers on Mar 1st. At 4:37 Air temp is 26.9C At 4:39 Air temp stabilised at 24.3 Ambient conditions on the day ➢ BOM data at 3PM was 34.2 °C & RH of 30 ➢ Ambient on roof was 31.2 °C and with 18% RH, this implies a Delta T of 12 °C To avoid false “wet bulb” readings, the probe was placed inside an electrical conduit. Ambient temperature was recorded as 31.2 C at 4:36 PM. The sprayers were activated to wet the mesh for a few seconds, then readings were taken with the probe and recorded as an MP4 file. Screen shots from the video show cooling progress.
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Case Study 2, Test 4: Observe discharge pressure during EcoMesh cycle (Mar 17th, 2016)
0:15 Discharge pressure 20.6 Bar 0:29 Sprayers activated (3 sec spray) 0:40 Discharge pressure 19.8 Bar Results: EcoMesh pre-cooling reduced the discharge pressure from 20.6 to 19.2 Bar 0:49 Discharge pressure 19.2 Bar 1:01 Discharge pressure 19.2 Bar 1:47 Discharge pressure 19.2 Bar Ambient at this time was 31 C (refer to Test 3). The discharge pressure was recorded for a dry mesh then monitored over the spray
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Case Study 2, Test 5: Return to site and observe mesh operating on a 41C day (Jan 17th, 2017). Ambient temperature at 4.00 PM: 40.9 C Discharge pressure from Test 4 (Mar 2016) at 32 C dry mesh, no pre cooling … 20.6 bar Ambient conditions on the day ➢ BOM data at 3PM was 40.0 °C & RH of 9% ➢ Ambient on roof was 40.9°C and with 9% RH, this implies a Delta T of 21 °C Discharge pressure Jan 2017 at 41 C with EcoMesh running … 21 bar! Inner coils at 4.00 PM: 27.4 C Outer coils at 4.00 PM: 37.1 C Results: The inner coils were cooled by 13.3 C. For a Delta T
estimated to be 63%. This is similar to the 58% and 60% efficiency achieved in the 2016 tests.
Discharge pressure gauge reveals that on a 41 C day, EcoMesh helps these chillers cruise as if it were a 32 C day!!
Follow up tests were done on this site one year after installation.
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Case study 2: Video of typical cooling - outer coils
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Case study 3, Test 1: Large chiller with Transverse V coils, York YLAA 6 fans, 1st March 2017
Between inner coils No pre-cooling 37.4 C at 3.34PM Results: The mesh cooled the incoming air into the coil from 37.4 C to 33.4 C or by about 4 degrees. On a York, the control panel coil has no cooling so only 5
see around 3 degrees and this corresponds to an efficiency of around 17%. Between inner coils With mesh, air-on 33.4 C at 3.44 PM Inner mesh, 31.9 C at 3.54 PM Ambient conditions on the day ➢ BOM data at 3PM was 37.9 °C & RH of 15% ➢ Ambient was 37.4°C and with 15% RH, this implies a Delta T of 18 °C
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Mesh is supplied as 1000 or 1200 mm wide panels that are installed along the front side, rear side and optional end to maximise coil coverage.
7.1 Mesh frame coverage
Mesh frame top brackets Tek screwed to cabinet top rail Mesh frame bottom brackets Tek screwed to cabinet bottom rail
Water header Tek screw bracket to top
Coil cabinet 1130 Over spray wets lower mesh
Mesh apex: 400 mm
Tek screw bracket to front of bottom rail
Mesh frame profile - Short mesh
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7.2 Power and water schematic (supply is customer responsibility)
Chiller “Running” contact:
are running.
each system should be served by separate water header/solenoid circuits.
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7.3 Water schematic (supply is customer responsibility)
Chiller cabinet Mesh 1 Mesh 2 Mesh 3 Mesh 4 Optional End Meshes 5&6 Mesh 1 Mesh 2 Mesh 3 Mesh 4 Control panel End stops Water filtration:
standard water filters to reduce salt content
KDF filters Mesh gaps approx. 0-60 mm Water headers (22mm aluminium pipe) Pressure reducing valve Solenoid valve with drain 2-3 bar Water filters Ball Valve Isolator Speedfit connectors Connecting pipework is 15mm copper Mains water Note: EcoMesh recommends up to 6-8 headers per solenoid valve to ensure consistent sprayer pressure at 2-3 bar. Main supply pipework is 20mm copper
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7.4 Water consumption
Each header has 3 x Fulco Tip “Full Cone” sprayers
WATER CONSUMPTION GUIDE: EcoMesh sprays every 30 secs. With a 2 bar water supply, each water header (triple sprayer) uses 3 x 0.0175 = 0.07 litres/sec. EcoMesh example: YLCA 4 fan chiller in a 3600 mm long cabinet Solution: 3 short meshes per side -- total of 6 meshes and 6 water headers. Standard spray cycle of 2 to 5 seconds. 6 water headers will consume 6 x 0.07 = 0.42 litres per second. At 30 deg C, system sprays 4 secs per min using 101 litres/hr At 45 deg C, system sprays 10 secs per min using 252 litres/hr
Fulco “yellow” tip nozzle flow rates: 1 bar – 0.74 l/min (0.0123 l/s) 2 bar – 1.05 l/min (0.0175 l/s) 3 bar – 1.29 l/min (0.0215 l/s) 4 bar – 1.49 l/min (0.0248 l/s) 5 bar – 1.66 l/min (0.0277 l/s)
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FOGGING SYSTEMS The mist is effective, but many nozzles are required. DIRECT SPRAYING Coil is constantly soaked. With EcoMesh, water is sprayed onto the mesh away from the coils.
EcoMesh has some unique features compared with other technologies
EcoMesh uses less water to achieve 25 to 45% efficiency. A 20 fan chiller will consume 700-900 litres per hour. With EcoMesh, the mesh traps most of the water. Also, EcoMesh sprays in 30 secs cycles and runs on mains water pressure. PAD SYSTEMS Use a lot of water to achieve 75%
consume 2700 litres per hour. Also … air is dragged through pads for the 330 days of the year cooling is not required. And pads deteriorate over time and need periodic replacement Other advantages:
mesh panel.
10 year life
prevent “bypass” air.
similar pad system
is required.
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Typical air flow into V side openings
Top of cavity (low volume): 5 m/s Upper (low volume): 7 m/s Middle (most volume): 5 m/s Bottom of cavity (low volume): 2 m/s Sub cabinet (low volume): 1 m/s Sub cabinet (low volume): <1 m/s
34 Mesh will have dirt or scale deposits over time. Hose down periodically to keep clean. Check water spray for “cone- shaped” spray pattern and 90 degree alignment towards mesh. Check mesh frame for loose brackets and tighten bolts if required. Check controller digital display – should be display correct ambient temperature reading Check water pipes and connectors for leaks. Check area around mesh for excessive water – evidence of a faulty sensor, connector or solenoid.
Turn system off during winter by isolating electrics and draining the pipes. Mesh can be unhooked and flipped up to access for cleaning
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EcoMESH
Supplied by: SBH Solutions 3 Ballantyne Street Magill SA 5072 P: 08 7122 1114 E: info@sbhsolutions.com.au