Innovative Energy Engineering

Commissioning (Cx)

Commissioning, as part of Quality Management, ensures the building systems work as intended. This can be a complex process requiring in-depth knowledge of the systems, the design intent and actual operation. Design review, construction verification, startup and testing are to be included. Maintenance staff and occupants should be involved in the process.

Retro-Commissioning (RcX)

Any existing system should be triaged:

Before any capital improvements, one should consider the "free" upgrades that improve the system at almost no cost. If the equipment is "not so bad", it often is out of tune or just needs minor upgrades to perform better. In many cases control sequences are not implemented as they were intended originally, which can be corrected.

If an addition to the building is planned in 5 years, it may be worthwhile to postpone the chiller plant replacement. One also needs to consider that capital investments often cause some disruption of the operation and take resources from improvements that would be more beneficial. In many cases a combination of both Retro-Commissioning and physical upgrade is the best solution.

In many cases replacement of or addition to existing equipment is the best choice for energy efficiency, reliability and maintenance. When making financial calculations, one should not forget that the 15 year old boiler we replace today, would normally require a replacement in five years anyway. This obviously requires a careful case-by-case analysis.

There are some spreadsheets and simple programs that attempt to calculate savings when replacing a certain type of equipment. However, those don't take into account actual efficiencies at different operating conditions, and don't take into account how the rest of the building or industrial process interact. In the end, it requires an energy simulation to predict savings.

Auditing Energy Performance

An audit evaluates a facility and compares it to comparable facilities. This is an ever ongoing process and energy consumptions should be monitored indefinitely. Additional information on Energy Management can be found on the EPA ENERGYSTAR Website.

Gather all and demand energy data for the recent years (12 months minimum) from the utility, fuel suppliers etc. Keep track of energy (Btu, kwh) and monetary cost separately and take advantage of any sub-meters etc. Keep track of the heating and cooling degree days to normalize for changes in weather (actually cooling depends on humidity and solar radiation too... but that is topic for a separate book itself). This information can be tracked in the EPA Portfolio Manager and in any spreadsheet. With this information we can determine the energy density per used area, produced unit or other industry standard unit. It may be necessary to gather that information from similar facilities for comparison.

It requires some expertise and knowledge of the operation of the building or industrial process, to gain some hints from the energy data themselves on where energy is wasted. The more detailed the data are (i.e. 15 minute electric demand data), the better. Often many affects cancel each other out, making it impossible to track down one specific problem by reading gross energy data only.

Now that you know how good (or bad) your building is, it is time to set goals. The simplest goal would be to perform as well as the average comparable facility. But the goal should be more aggressive and we can target to achieve what the best in the industry achieved.

Verification

After measures are implemented, they need to be monitored. We need to know they are incorporated correctly, and that the savings actually are there. In a large facility without sub-metering it may be hard to see the impact of a small measure. Once actual savings are shown, stake-holders see that energy efficiency measures are worthwhile. No matter how much savings a calculation predicts, most people say "show me".

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