Armstrong In The Media

10 Ways to ensure your HVAC system is energy efficient

Posted by Armstrong Fluid Technology on Oct 17, 2016 6:00:08 AM

10impeller#10: Is your pump manufacturer building inefficiency into your project with standardised pump impeller sizes?

Some pump manufacturers standardise on a set range of pump impeller sizes and round up to the nearest size for your required duty. This oversizing builds in inefficiency from the start and clocks up energy wastage with every revolution. Insist on having your pump impellers trimmed by the manufacturer to optimise motor power and drive out these wasteful practice.

Armstrong Fluid Technology always trims pump impellers specifically for your requirements and our IVS controls’ load limiting function automatically slows the pump down to avoid overload situations.

9maintenance#9: Is routine maintenance of your pumps more costly and time-consuming than necessary?

Changing seals is a necessary routine maintenance task. For large traditionally-designed pumps, this can involve multiple engineers, lifting equipment and specific health and safety regimes.

Cut maintenance times to a minimum with split coupled pumps (for example, Armstrong Design Envelope 4300 pumps).  The split coupling enables all mechanical seal components to be withdrawn for servicing without the need to disturb other pump components or the motor connection. There is no need for special lifting equipment for larger pumps, and seal changes can be carried out in hours rather than days. Armstrong 4300 pumps are also engineered to the very highest standards with a dynamically balanced impeller, and a shaft assembly rotating vertically on the pump centreline for quiet, long lasting operation with minimum vibration. Vertical mounting of the pump also extends bearing life.

8floorspace#8: Could you save valuable floor-space?

Specifying pump accessories such as the Armstrong Suction Guide and Flo-Trex valve can reduce plantroom footprint considerably. The Armstrong Suction Guide creates the optimum flow conditions at the pump inlet with a single component, eradicating the need for the conventional Y Strainer, flanges, nuts, bolts, gaskets and suction spool piece. At the discharge outlet, the Armstrong Flo-Trex combination valve carries out the functions of a check valve, throttling valve and shut-off valve with just one component. So an Armstrong 4300 pump with these fittings may need just a third of the space required for a traditional base mounted end suction pump.

7payingmore#7: Are you paying over the odds for pump installation?

Traditional pump designs require significant investments of time and money to anchor them in place.

For a better solution, specify vertical inline pumps designed to be pipe-line hung (such as Armstrong Design Envelope 4300 pumps). These pump models are designed to be integral components of the pipework, eliminating the cost of inertia bases, springs, flexible pipe connectors, field grouting and alignment. They can be suspended above the floor for ease of cleaning or to enable other system components to be installed underneath, to reduce plantroom footprint.

6boosters#6: Are constant speed booster sets undermining your building’s environmental performance?

Traditional design strategies involve specifying pumps for booster systems based on peak flow rate (a condition that may occur for only a short period of the day). As a result, for the majority of the day, pressure boosters are over-pumping, consuming unnecessary amounts of energy.

An improved solution is to install variable speed booster sets capable of adjusting to steep changes in load profile. These booster packages (such as the Armstrong Design Envelope 6800 Vertical Multistage Boosters) provide constant pressure regulation without the significant energy losses associated with pressure-reducing valves.

5manufacture#5: Should you be capitalising on the benefits of off-site manufacture?

Large commercial and public sector buildings are typically high profile construction projects, situated in busy, urban centres, involving extensive supply chains. This complicates communication, access, health and safety and scheduling.

Off-site manufacture is the answer. Assembling an integrated plantroom in Armstrong’s factory, and delivering it to site ready for final connections, provides major benefits. Contractor traffic can be minimised, health and safety risk is reduced, and disruption in crowded city centres can be avoided. Assembly of the plantroom can also continue during the construction phase of the building, rather than having to wait until the building is completed. 3D modelling technology during design also improves communication between parties and streamlines delivery and installation.

4boilers#4: Are you optimising boiler efficiency?

High-tech boiler plant often fails to operate at its optimum efficiency due to wrongly set return temperatures. In North America and the UK, low temperature hot water heating systems were traditionally designed with a supply temperature of 80°C (≈180°F) and a return of 70°C (≈160°F). But that is too high for today’s high efficiency system components. With the latest generation of condensing boilers, for example, if the return temperature exceeds 54°, there is every reason to expect that the boilers will never actually condense! The difference in efficiency can be as much as 10% depending on boiler type and load.

More effective maximum system temperatures would be 70˚C supply and 50˚C return or, to condense continuously, 50° supply and 30° return. The Armstrong MBS fully-integrated modular boiler system enables boiler efficiencies to be achieved and exceeded automatically. It incorporates fully modulating boilers, variable primary pumps, automatic fill/pressurisation unit and integrated controls, all pre-specified for optimum efficiency, and supplied ready for rapid assembly on site.

3controls#3: Are you driving outstanding efficiency by operating each HVAC system component along its ‘Natural curve’?

Due to the pump fan laws (power is proportional to rotary speed cubed - P a N3), the operating efficiency of a rotating device can be increased by 400% if it is allowed the flexibility to operate along its Natural Curve. These efficiency improvements can only be achieved, however, if the pump fan law relationship between pressure and rotary speed, along the Natural Curve, is maintained at the decreased speed.

Traditional control practices, however, often create situations in which components are forced to under-perform. For example, a fixed or minimum differential pressure being maintained across pump supply and return headers. This means the pump will not have the freedom to operate along its Natural Curve and will, consequently, consume more energy.

An effective alternative is to employ advanced integrated control (such as those that reside in the Armstrong Design Envelope pumps) to ensure that pumps, in addition to other variable speed devices, are operated automatically along their Natural Curves to optimise efficiency.

2controls#2: Could better equipment staging revolutionise your building’s efficiency?

Whilst many system designs incorporate components that are individually energy-efficient, this is not sufficient to meet today’s ambitious levels of environmental performance.

To really perform at its full potential, the HVAC system control strategy must have the capability of satisfying operating loads by determining the best net system efficiency and trading off power efficiencies among the system components in relationship to one another. An Equal Marginal Performance Principal control methodology (such as those that reside in Armstrong Fluid Technology solutions) can calculate and determine the best power relationship between individual components such as chillers, condenser pumps and tower fans, to achieve this objective automatically. The resulting trade-off may operate a greater number of devices at lower speeds to take advantage of the affinity laws. This results in cubed power savings and utilises larger heat transfer area than is created by operating either two devices at 50 percent or three devices at 33 percent.

By maximising critical cooling chilled water system efficiencies to Ultra-Efficient levels in this way, for example, energy use could be reduced by up to 60%.

1ifms#1: Could you future-proof your building more effectively?

The usage and occupancy of a building changes throughout its lifetime. In the case of IT-intensive buildings such as data centres, there is a deliberate strategy to increase cooling load incrementally over time, in line with increasing processing capability. Over-sizing equipment at the outset, or replacing equipment within short lifecycles, in order to accommodate these changes, is hugely wasteful. It also frontloads capital expenditure unnecessarily.

Armstrong Fluid Technology’s Design Envelope concept avoids these problems by providing key HVAC components and systems (such as the Armstrong Design Envelope 4300 pump range) which can offer outstanding energy efficient performance across a wider operating envelope than ever before. Designed with a built-in safety net, they eradicate the need to trade-off the energy efficiency of the installation through over-sizing equipment “to be on the safe side”. Incorporating Armstrong’s award-winning on-board inverter control feature, they adjust quickly to changes in load to optimise energy efficiency of the system automatically, across a wider range of operational conditions than any other available pump range.

For projects that will benefit from an incremental increase in HVAC capability, Armstrong iFMS packaged pump solutions provide a modular solution making it possible to ‘bolt-on’ additional cooling or heating over time. In addition to avoiding the energy wastage of over-sized plant, this assists profitability by preventing the need to front-load capital investment, whilst meeting the demand for predictability and reproducibility of environmental performance.

Find out more at the Armstrong Fluid Technology Sustainable Cities Conferences

London, November 3rd 2016 (Register now)
Manchester, November 8th 2016 (Register now)


Topics: Energy, In The Media

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