HVAC – Automated Heating, Ventilation and Air Conditioning System for Office

HVAC Automated Heating, Ventilation and Air Conditioning System for Office

A Test Bed for Smart Buildings
Schneider Electric’s Le Hive automates energy efficiency. Traditional techniques such as adding insulation or window caulk can make buildings more energy efficient, but those strategies go only so far in reducing energy bills. Smart building systems linked to the smart grid offer a more comprehensive way to reduce consumption.

Retro-commissioning Commercial HVAC systems

Is it “Retrocommissioning” or “Redesign”?

 

Retrocommissioning is a new term for a process that has been implemented by engineers, service contractors, controls contractors and service technicians for years.  Many have taken “problem” systems and corrected the issues by a disciplined step-by-step approach correcting airflows, deferred maintenance, relocated sensors, settings and re-establishing sequences of operations.  The corrections (retrocommissions) can run from a building use problem (the microwave in the lunchroom has been placed under the sensor) to a diffuser location that is incorrect after an office renovation; to a lack of any maintenance on the systems; to a system with airflow issues due to a lack of balancing or commissioning of the original installation.    

 

Redesign by contrast looks at the building HVAC layout, building use and changes that have occurred over time since the original installation and deduces that the building will be best served by a completely new application of HVAC equipment and air/water distribution.  The redesign is usually a higher initial cost for complete system replacement but may be the best answer for improved comfort, indoor air quality, efficiency and building use.  

 

Ask yourself this question……Does the building have good “mechanical” bones?  Is the basis of design (i.e. the system layout itself) operable to serve the present use of the building?  Does the duct system (irrespective of the controls, dampers, etc) distribute air to the building effectively?  Can we work with the “mechanical bones” of the building and upgrade the muscular structure (the dampers, controls, ventilation, etc.)?  This determination needs to be the starting point towards a discussion of retrocommissioning or an ultimate upgrade or redesign of the building’s mechanical systems. 

 

The decision on whether to redesign or retrocommission can be made on initial visits and cursory review of the existing layout and distribution of the ductwork, piping, electrical and controls.  At this point, a retrocommissioning will take you in one direction while a building leaning towards some element of redesign or an entire BAS (Building Automation Systems) or EMS (Energy Management Systems) replacement will lead you towards budgetary and scope discussions.  Involving the owner and owner’s maintenance personnel in the initial discussions and getting them involved in the process will increase communication and commitment to the best end result. 

 

If systems are inherently sound and layout of the building has not completely changed then “retrocommissioning” is the best option while including some small design/layout changes that are not exceptionally costly. However, if the building has undergone a complete change in the use and operation of the space (i.e. the spaces used to be “labs” and have now become “offices”) then it is a candidate for a complete “redesign”.  New requirements for outside air, newest ASHRAE standards, energy efficiency considerations, air flow and water flow zoning improvements and today’s indoor air quality standards will all be part and parcel of the new “redesigned” HVAC systems. 

 

Original construction dollar and time limitations dictate that EMS or BAS are only as effective as the installing contractor left them and are dependent on the ability of the controls contractor to correctly locate and apply sensors, variable frequency drives, actuators and system layout.  Some of items such as system layout and sequence of operation are in the designing mechanical engineer’s arena of the project. However, the ever-present “canned” specifications or sequences of operation in Bid/Spec.jobs and the chilling term….”field verify” leave the “Actual” sequences and specifications to the decision of the low-bid installing contractor.  With most original construction contracts becoming more “value engineered” after the fact and as a result of the reduction of original capital dollars on the part of the building owners, systems are installed to the best ability that the contract dollars will allow.  This assures a large group of buildings that will, with the passage of time, become “opportunities” for re-design or retrocomissioning. 

 

The process of correcting/improving systems and their operation should NOT include any “finger-pointing” at facilities maintenance, service contractors or comments about the original engineering.  Anyone can have 20/20 vision in hindsight!  All of the installation and maintenance work on the aforementioned systems has been done by engineers, contractors and technicians who care enough to want people to be comfortable and for buildings to operate as good as or better than designed.  Our goal is to care about our trade (HVAC) enough to help correct problems and to convince owners that a well ventilated, energy efficient, comfortable building is in everyone’s best interests.  Partnering with them to do this in a cost-effective and consultative manner assures success stories and goodwill for the HVAC trade as a whole.

 

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HVAC – Automated Heating, Ventilation and Air Conditioning System for Office

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