Editorial Contact: Mike Leeming
Parker Boiler: National Sales Manager
Direct Tel 323-727-9800
Parker Boiler: Industrial Boiler Specialists
Web site www.parkerboiler.com
SUBJECT: EFFICIENT HOT WATER SYSTEMS for industrial boilers
FOR IMMEDIATE RELEASE Wednesday, February 06, 2008
In this years’ August ASHRAE Journal, Kent Peterson, ASHRAE’s current 2007-2008 President, wrote an excellent inspirational article motivating those of us in the HVAC Industry to do our best to create sustainable energy efficient designs. I have had the pleasure of working with Kent over the years and I can tell you his designs do push the technology envelope and challenge us to build better, more efficient, clean burning and sustainable equipment.
Case in point is Kent’s design for 10 of our T6800LR Low NOx Hot Water Boilers which have been on line at CSU Long Beach Central Plant for the last 12 years. These boilers achieve efficiencies of over 84.5% while running within the terms of their SCAQMD permit.
While thinking about the article and our experience on hot water systems, I was reminded that the following items must be integrated correctly for a system to operate as it was intended.
- The boiler is part of a system.
- The system designer (HVAC Engineer) is the responsible individual for the system.
- Without proper design, follow up, commissioning and maintenance, the system will not operate as intended or be energy efficient.
We are in the fortunate position of getting involved in the design of all types of hot water and thermal fluid systems and we have developed the following list of questions or thoughts which hopefully you’ll consider as you embark upon your next hot water system design:
I – Boiler: Important Selection Criteria
- Operational Temperatures
- Ease of Maintenance
- Size constraints
- Operating hours
- Pressure/Temperature Requirement
- Venting requirement
II – Type of System
- Number of boilers versus size of load (for instance, 1 boiler @ 100% load, 2 boilers @ 50% or 75% of load)
- Design Temperature and Temperature rise through boiler
- Coil DT and type
- Number & GPM of Pumps
- Number of pumps to normally run
- VFD Pump Operation
- Methods of resetting Hot Water System Temperature (if desired)
– On boiler
– By primary secondary pumping
– 3 way valve
– By BAS
- Limit of HWS & HWR Temperatures
- Ways to maintain boiler flow
– 3 way valves at terminal units
– End of main(s) bypass (each floor)
– End of main circuit setter
– Bypass valve (pressure actuated)
– Primary/secondary pumping
– Run around pump on boiler
- Flow control valves on multiple boiler jobs
- Method and control strategy for starting and stopping system
III – DDC Interface/Controls
- Start – Stop
- Alarm D.C. for any failure
- Burner On Status Indication
- Operating Control Function
- Control of Modulating via 2-10 VDC or 4-20 ma signal
- Flow Switch
- Reset of HWS Temperature from BAS
- Lead lag system for boilers (normal or parallel lead lag control)
By addressing all of the above you can be assured that proper consideration will be given to create an efficient effective system.
In many instances, you are dealing with an existing building which forces your hand in type of system, venting, and piping arrangement.
About Parker Boiler
Parker Boiler manufactures a full range of steam boilers, hot water boilers, thermal liquid heaters, indirect water heaters, low NOx burners, water softeners, feedwater return systems, feedwater deaerators, blowoff tanks, storage tanks and boiler room accessories.