This post will begin a list of ECMs (Energy Conservation Measures) related to HVAC and lighting in hospitals. Since my area of expertise is HVAC controls, I will be spending more time on this topic than lighting. This post will be followed by at least four more posts in the following areas; HVAC, working with the sun, lighting control, and building automation system changes.
There is a lot that can be done to save energy hospitals. With a good model of the building, a solid baseline, and good metering a detailed list of applicable proposals can be made. Most ECMs sound good taken in the abstract. You may find that many of these measures are not applicable or cost effective for a given project once they are screened against local climate conditions, building use considerations, local regulations, and incentives.
To achieve the highest levels of efficiency from any building, it will be very important to have a good record of the building's current consumption and the outside air temperature and humidity. Ideally, these will be obviously related. If they do not track each other well, this can indicate opportunities to "right size" or schedule equipment so that output can be more closely matched to demand.
In General
Process Changes and the regulatory environment - Incentives can play an important role in energy costs. For example, certain commercial rates in the USA are paid based on peak demand. You will get a lower rate per kWh, but you must pay as though you were at your peak consumption for the entire month. This would incent you to keep consumption steady and prevent any spikes. Changes in process and the timing of events could greatly impact your costs. For example, by monitoring consumption in real time the control system can be programmed to shed non-critical loads and alter set points to stay under a given threshold.
Trending and Continuous Commissioning - Before I dive into specific technologies which could be applied here, I would like to point out a problem that can occur in newer buildings. Buildings that employ newer technologies and employ creative applications of technology are the most susceptible to poorly executed maintenance. This may seem like a small matter and an uninteresting topic, but inattention to this problem is very costly. Maintenance personnel must understand the operation of the system and the reasoning behind the use of certain technologies. In many cases, there will be a trend toward simplifying systems and maintenance procedures at the expense of energy efficiency.
An occupied building with complex systems should employ frequent retro-commissioning. A lot of energy is wasted in buildings that are not performing to their potential simply because systems are not maintained properly, or have experienced an accumulation of minor failures. An automation system may mask problems like leaky valves and higher than necessary pressures which lead to waste. I believe most facility managers or owners would do well to employ someone to perform an ongoing analysis of systems information to ensure that everything is always performing optimally. I have had positive experiences with Cimetrics providing this sort of service with their Infometrics offering.
As an example, heating and cooling valves should be checked for proper operation. If a heating valve is closed and the supply air is still heated by the coil, the valve isn?t seating correctly and can cause simultaneous heating and cooling. This condition could be alarmed and reported so that corrective action can be taken.
Right Sizing and Matching Equipment to Current Applications ? Mechanical systems are often oversized or engineered for worst case scenarios. After a building is occupied and the actual use is known, there may be opportunities to correct the size and control sequences for equipment. Similar problems with size and control can also happen when areas of a building change function. If a system is too large, or delivers too much ventilation the tendency would be to leave it alone due to the impact on the first costs of a project.
An Example of incorrect sizing or incorrect sequences would be a lab space that had an extremely high number of air changes per hour (ACH) that has since been converted to office space. While the high number of ACH is not harmful to occupants, the cost to run the system is much higher than necessary.
In the near future I will post specific ECMs. In the meantime:
IF YOU KNOW OF A BETTER METHOD, LET ME KNOW!
