issue 35 sav commissioning modules how low can you go?
TRANSCRIPT
Low Carbon Energy Solutions for Building Services
www.sav-systems.com
SAV Commissioning Modules for Ultra Low Flow and standard flow hydronic systems
For quick, easy and accurate
compliance with CIBSE
Code W and the BSRIA
Commissioning Guide –
whatever the flow rate!
Tackling ultra-low flows
As buildings have become better insulated, with
lower space heating demands, variable volume
hydronic heating systems have become much
more common.
The result is that commissioning engineers
often find themselves dealing with ultra-low
flows (<0.015 l/sec), where the flow rates are
too low to measure accurately and consistently
with standard flow measurement devices.
“Specifiers are required to identify an
appropriate commissioning method for
ultra-low flow system designs. “
- CIBSE Code W
To address this issue, SAV Systems has
introduced Ultra Low Flow Commissioning
Modules to its FloCon range, using patented
valve technology.
These modules overcome the problems of
ultra-low flows by connecting groups of
terminal units to a single, compact manifold
that includes a differential pressure control
valve (DPCV). The module then acts as a
‘control centre’ for commissioning, enabling
flow measurement by subtraction – one of the
methods recommended in the latest revisions
to CIBSE Code W (see inside).
SAV Commissioning Modules - How low can you go?
A recent BSRIA study on fan coil
systems using Commissioning
Modules showed significant
time-savings compared to
traditional systems with
commissioning valves on
individual terminal units.
•28% saving on installation
time
•43% saving on flushing
horizontal mains pipework
•23% saving on flushing fan
coil unit circuits
•44% saving on commissioning
Issue 35
SAV Commissioning Modules -Technology you can rely on
Ian Green, SAV Project Manager
SAV FloCon commissioning module which is pre-fabricated and tested off site. Designed for quick installation, accurate commissioning, easy maintenance and efficient pumping systems.
www.sav-systems.com
www.sav-systems.com
Designing systems with
ultra-low flows can make a valuable
contribution to reducing energy
consumption and carbon emissions.
However, such designs bring their
own challenges.
CHALLENGE 1:
How to deal with ultra-low flow rates.
SOLUTION:
SAV Ultra Low Flow Commissioning Modules facilitate the subtraction method of commissioning, one of the methods approved in the CIBSE Commissioning code W 2010 - water distribution systems.
The subtraction method, which can reduce commissioning times in both ultra-low flow and standard flow hydronic systems, is as easy as 1, 2, 3:
1. The flow through all of the terminal units connected to the commissioning module is measured to obtain a combined flow rate.
2. When one terminal unit is isolated, the flow rate through the remaining terminal units is still high enough to measure.
3. The difference between isolated terminal unit and combined flow rate of all terminal units is equivalent to the flow rate of the unit that was isolated.
Commissioning modules
A Commissioning Module essentially acts as a
distribution ‘hub’ for a group of terminal units
(typically up to seven) and enables commissioning
to be carried out from the location of the module.
Commissioning Modules are typically pre-
fabricated and pre-insulated offsite under factory
conditions and pre-tested before delivery to site.
Each module incorporates all of the valves required
for commissioning, including 2-port actuated
control valves and a differential pressure control
valve to ensure that all 2-port control valves
operate with excellent authority.
In addition to the time-savings, Commissioning
Modules offer a number of other significant
benefits, including:
•Benefits of pre-fabrication
•More effective use of skilled operatives on site
•More precise measurement of ultra-low flows
• Supplied in insulated box with vapour-sealed penetrations
•No need to disturb insulation during commissioning
• Facilitates use of flexible pipework
•More flexible solution for end client
Ultra-low flow module.
SAV Systems HVAC Commissioning
Product Brochure
Flocon - Ultra-low flow and standard flow headers
CHALLENGE 2:
How to minimise pump energy consumption in pipework systems.
SOLUTION:
SAV Commissioning Modules can be used in conjunction with ‘remote sensor’ pump control, delivering higher efficiencies than those achieved with constant flow systems.
Using remote sensor control, the pump speed is controlled such that the pressure differential across the pump reduces towards the design pressure differential across the most remote pressure controlled sub-branches (or modules). Differential pressure sensors, wired back to the BMS or pump, are required across the selected sub-branches/modules.
Variable speed pump control
Used in conjunction with properly designed variable speed pump control, modules can achieve energy savings in the range of between 65 -70% relative to traditional constant flow systems (source BSRIA Guide BG12/2011). The bar chart below summarises the potential energy savings attributable to modular based designs for a typical system.
CHALLENGE 3:
How to address the problem of dirt settlement in pipes carrying ultra-low flow rates.
SOLUTION:
SAV’s AluFlex flexible piping systems are available down to 14mm nominal diameter (10mm internal diameter) pipes to help increase water velocity.
AluFlex flexible piping systems
SAV’s AluFlex piping systems are ideal for use with
SAV Commissioning Modules, enabling faster and
more reliable installation with no requirements
for elbows or bends. Connections are made with
Pressfit fittings, saving even more time.
•Connection is only required at the ends.
• Faster installation, fewer connections, no elbows or bends.
•Assists compliance with BSRIA guidelines for reducing installation times.
• Fewer connections reduces the risk of leaks.
• Easy to fit, with no requirement for specialist skills.
•Robust design, resistant to rough handling on site.
•Rated for temperatures up to 95degC and a working pressure of 12 bar
• Life expectancy of 50 years, full guarantee for 10 years.
•Gas-tight against oxygen, reduced risk of corrosion.
BSRIA Guide BG12/2011 Design of Energy Efficient Pumping Systems
Released in 2011 with recommendations on how to minimise pump energy consumption in pipework systems.
CONSTANT FLOW
Pump speed constant Pump speed controls maintain constant pressure
across pump
Pump speed controls maintain pressure at most remote DPCV
VARIABLE FLOW
4 Port Valves
Modules + 4 Port Valves
2 Port Valves + DPCV’s
DPCV Modules
Rela
tive
pum
p en
ergy
con
sum
ptio
n (%
)
Copper Multilayer
Nom. Diameter
Flow Rate (l/s) at 0.5m/s
Nom. Diameter
Flow Rate (l/s) at 0.5m/s
15 0.072 14 0.039
22 0.158 16 0.057
28 0.262 20 0.100
For further information contact:SAV Systems, Scandia House, Boundary Road, Woking, Surrey GU21 5BXTel: +44 (0)1483 771910 Web: www.sav-systems.com E-mail: [email protected]
www.sav-systems.com
“The SAV solution offers
more accurate control of
differential pressure and easier,
faster commisioning - a sixth of
every floor at 30 St Mary Axe,
could be balanced and finely
tuned from a single point.”
- Dave Gatwood, Project Manager,
Hills Mechanical
University of Liverpool, Central Teaching Labs.
Bishopsgate, Central London. New Cannon Street Tube Station building.
One Hyde Park, Central London. Harvey Nichols Department Store, Central London. London Stock Exchange.
SAV Commissioning Module
30 St Mary Axe.
“The benefits at the
commissioning stage have
been remarkable. There were
zero problems in a 125,000 ft2
building! Our commissioning
engineers describe the Modules
as “a dream to work with” and
all their figures were within the
design set margins.”
- Stuart Bareham, Waterman
Building Services
SAV Systems is proud to have supplied FloCon commissioning modules to a number of prestigious buildings and businesses throughout Britain. SAV always aims to deliver innovative solutions to the benefit of clients, consultants and contractors.