Tip of the Hat - Moduline VAV
Quality, Consequences and the Construction Industrial Complex (part 233).
Its throw back Friday.........what if I told you there is a VAV system that is:
- Capable of working in VAV or CV applications
- System powered i.e. no field power or controls wiring required
- Autonomous local control with no wall mounted control unit
- Low cost to install, run and maintain
Well there was and is such a system, it is the Carrier Moduline system. During the 1980's and part of the 1990's these systems were popular in the UK. The Carrier UK website still has info on them (https://www.carrieraircon.co.uk/product/37ah/)!
I have not seen Moduline installed since the 2000's. I think this is because HVAC design engineers feel that the best response to the demand for high performance buildings is adding complexity and vastly extending the BMS system.
Whilst I am a huge fan of measuring as much as possible I believe the best design response to deliver high performance buildings is simplicity and very targeted measurement and control.
IMHO, VAV systems are outdated 1970's technology that we should have moved on from. However, VAV systems persist due to:
- Path dependency (the most powerful influence you are not aware of)
- Entrenched supply chains (the largest influence on design decisions)
- Rewards for maintaining status quo i.e. zero risk taking (the second largest influence on design decisions)
- Energy modelling rewarding VAV (incorrectly in my view)
I was reminded of how good Moduline is on a building audit and RCx project in Canada. Sometimes it is good to be old and experienced. I was the only person who recognized the VAV system as Moduline and knew how to test and set it up. I even found my old Moduline technical manual which can be downloaded from my website here ( https://bldwhisperer.com/free-downloads/ ).
So to recap, there is a VAV system that has no field controls or small power wiring, no wall thermostats, minimal BMS points, is easy to maintain and run mostly because there are less options for maintenance technicians to change BMS set points.
All hail the Moduline system!
Stay inside and be safe everyone.
BlueRithm Brand Ambassador www.bluerithm.com
Twitter @BLDWhisperer
Related Posts & Links
#93 - VAV Box Calibration https://bldwhisperer.com/vav-box-calibration-trust-but-verify/
#94 - VAV Box Sizing – Rules of Thumb Vs Engineering https://bldwhisperer.com/vav-box-sizing-rules-of-thumb-vs-engineering/
#101 - VAV Control Sans Duct SP Sensor https://bldwhisperer.com/vav-control-sans-duct-sp-sensors/
Edifice Complex Podcast
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Operations Director at BEECH TECHNICAL SERVICES LIMITED
4 年I tend to have a differing opinion on the long term maintenance costs. The regulators after a number of years tend to read lower than their stated duty even when the filters are well maintained. This was due to debris build up in the regulator, thermostat bimetallic strip and degrading of the rubber tubing. I am still armed with my book, charts and commissioning caps. We used to remove half a dozen and fit new controls sets, the others were cleaned in an ultra sonic cleaning bath and where then rotated with others until the system was clean and fully operable.
President at Precision Flow Engineering
4 年Keeping with the theme we just rebalanced a building with the old KMC stand alone controls. These were the kind where you calibrate the box using a dc volt meter at the stat. Sure there were some bad components here in there but we were all struck by how accurate they were and how well they had stood up to the years. Like you implied: No way for building operators to change set points without getting out some tools.