Vendor Response: Power Systems Part 2 The following is the second installment of our vendor responses concerning Spring 2009's Build It Right column on Power Systems.
The Spring 2009 issue of Healthcare Building Ideas featured a new regular department titled Build It Right wherein a selection of experts (an architect, engineer, maintenance expert, and owner) are asked questions about current considerations for installing, using, and maintaining systems such as roofing, flooring, IT infrastructure, etc. The latest column was focused on Power Systems. We asked several vendors to comment on the article by answering a series of four questions. The following is the second installment of their responses (read the first here).
Your thoughts about cogeneration as an option?
Dan Draper, Liebert products healthcare marketing, Emerson Network Power
The U.S. Department of Energy reports that U.S. hospitals spend more than $5 billion annually on energy, which equates to at least 15% of a hospital's profit margin being tied up in energy costs. Prices and demands are only going to keep rising, so when a facility has an opportunity to implement a cogeneration or combined heat and power (CHP) plant, it's a must do. Complete payback of the investment is typically less than five years thanks to subsidies and tax rebates.
Chuck Gougler, Marketing Manager, Staco Energy Products Company
Many facilities will consider cogeneration, however, this is truly a cost/ROI issue.
Martin Olsen, Vice-President, Business Development for Active Power
Cogeneration as an option to being fed from the utility is an interesting option and currently represents approximately 8% of energy consumption in the United States. Any growth in this number requires a substantial, and to some extent, a unilateral legislation and/or incentives from a federal standpoint as the rate of deployment has largely exhibited the typical state-level silo management outside of the federal government. Examples of cogeneration centrally managed are ample with Denmark as the prime example, recycling approximately 55% of the heat produced and distributed to households through a vast network. Any large-scale success requires volume to scale this economically.
Wissam Balshe, Cummins Power Generation Inc.
Although the principles of cogeneration have long been known and implemented in a wide variety of applications—including providing electricity and space heating to modern processing facilities and municipal utilities—the economies of scale previously favored large complex projects for special situations. However, due to the advances in diesel and lean-burn gas engines, heat exchanger and system control technologies, cogeneration is now becoming a practical and economical energy management solution for applications in healthcare facilities, hotels, sport centers, nurseries, commercial, and industrial facilities.
Cogeneration, also known as combined heat and power (CHP), normally consists of a prime mover turning an alternator to produce electricity, and a waste heat recovery system to capture heat from the exhaust and cooling water jacket. The prime mover can be a diesel engine, a lean-burn gas reciprocating engine, or a gas turbine. More than 90% of the energy in the original fuel is put to productive use, making the system energy efficient, and significantly reducing energy consumption and costs (around 35% or more). This on-site power generation system will increase your power reliability, expand your facility’s capacity, and minimize your operation’s greenhouse gas footprint.
Keep in mind that cogeneration systems are not typically designed to provide all the facility’s electrical power requirements, but only a portion of the total electric and thermal demands. This portion is usually equal to the base-load energy needs for your facility. The peak energy needs will still need to be supplied by the electric utility and on-site boilers or furnaces. To determine if the facility is a viable candidate for cogeneration, the analysis needs to address three key economic factors:
a favorable ratio between the local cost of natural gas and the cost of electricity
a simultaneous base-load need with at least 300 kW of electricity and about 1 MMBtu/hour of thermal energy
eligibility for government incentives and rebates
If the application is right for cogeneration, and the natural gas costs are low relative to electric rates, then I recommend consulting an energy expert or advisor for a formal economic analysis before considering the installation of a CHP system at your facility.
What are some energy-saving options that seem practical?
Dan Draper, Liebert products healthcare marketing, Emerson Network Power
While it's not a new piece of equipment or revolutionary idea, a centralized monitoring and control system is a great investment. Precision controls for cooling units allow a facility to dial in the optimal and most efficient operating parameters. Being able to remotely monitor power and cooling also improves efficiency of staff resources as facilities and network services personnel are no longer responding to false alarms, testing batteries, or investigating hot spots.
Chuck Gougler, Marketing Manager, Staco Energy Products Company
Designing new facilities and improving existing facilities to allow for improved energy savings is typically part of the agenda. Specific to the electrical network, use of the appropriate lighting and controls is a must. Other areas include evaluation of the electric bill, where poor power factor may substantially drive monthly electric costs upward—installation of power factor correction will immediately reduce costs and generally offers an acceptable ROI/payback. Harmonics and other areas of power quality should be reviewed to help assure maximum electrical power system performance, while helping to manage energy efficiency, cost, and minimize potential problems to equipment operating on various loads.
Martin Olsen, Vice-President, Business Development for Active Power
Although impractical to implement across the entire consumer and industrial user base, a change to 415V—similar to the distribution scheme in Europe—would yield a significant reduction in both capital and operational cost. If we take a data center as an example, thousands of servers are fed by 120V or 208V power. Almost any server sold in the United States can be deployed in Europe without any changes to its hardware and be fed 220/230/240V, which is their single-phase distribution scheme. 230V is the phase to neutral voltage derived from their 400V, three-phase main building distribution. In the United States, the most common building distribution voltage is 480V. As a result, we require a step-down transformer to 208V to achieve the ultimate phase to neutral 120V power to our servers. Employing a 400V or 415V distribution scheme in a data center takes out the transformation step of 1–2% losses and eliminates costly copper-wound transformers, reducing the size of copper cables now carrying less current, and ultimately boosts the power supplies in the servers another 1–2% in efficiency because of the higher voltage. This is perfectly possible and practical in most data center environments among others.
Wissam Balshe, Cummins Power Generation Inc.
Efficient energy is achieved primarily by means of a more efficient technology or process rather than by changes in individual behavior. Some simple techniques for achieving energy efficiency include ensuring that the electrical load is balanced between the three phases, insulating your building to use less heating and cooling energy to achieve the same temperature, and installing fluorescent lights and/or skylights instead of incandescent lights to attain the same level of illumination.
You will save energy by taking such measures, but in order to truly reduce energy use at your facility, you should consider investing in smart technologies, such as using variable frequency drives on your fans, pumps, and motors, and working with your local utility to install advanced metering and controls devices that would shut off your noncritical loads during peak demand hours, and finally consider cogeneration systems.
For further information, consult with a Leadership in Energy and Environmental Design (LEED) certified engineer to help design your facility.
What are some considerations for a power supply upgrade in a facility renovation?
Dan Draper, Liebert products healthcare marketing, Emerson Network Power
Power supply upgrades are usually necessary because need has outgrown existing capacity. It's important to not only address today's need but also to take the time and lay the groundwork for the next expansion - because it's likely going to happen someday. While budgets are tight, many of these steps have minimal cost. Setting aside floor space for a new UPS to serve a future wing of the hospital, installing conduit and ductwork to areas that someday will have power and cooling requirements, and evaluating the size of the switchgear if eventually more generators are added, are smart steps that can save millions during the next expansion project.
Wissam Balshe, Cummins Power Generation Inc.
The major considerations for upgrading your power supply system during a facility renovation is understating how much capacity you have remaining on your emergency equipment; the type of equipment used in your distribution system, such 3-pole or 4-pole transfer switches; the need to meet the selective coordination requirements, as defined by the 2008 National Electric Code (NEC); and the effect of the new loads added to the facility on the quality of power that will be supplied by your high-impedance power supply systems such as generator sets. You especially need to consider the impact of using nonlinear loads that induce high levels of harmonic distortion on the power system.
The NEC code requires that you protect your system from ground faults, so an analysis needs to be performed on the power distribution system to ensure that the grounding and bonding of a 3-phase, 4-wire power system, does not have multiple paths for the ground fault current to flow in, and that the fault current always returns to the source on one path to properly detect that fault. This may require upgrading the facility to a 4-pole transfer switch, and that could be an expensive retrofit. Therefore for a grounded Wye, 277/480V, we recommend specifying a 4-pole transfer switch even if the code allows the use of 3-pole transfer switch. This will help eliminate multiple ground fault paths, and avoid nuisance tripping of the over-current devices in the facility.
The other major challenge for upgrading the facility’s electrical system is ensuring that the protective devices are properly coordinated, which is difficult when using multiple contractors that use circuit breakers from different manufacturers.
My recommendation is to use protective equipment from the same manufacturer, if possible, and to eliminate circuit breakers when not needed on equipment that utilizes inherent protective devices such as protective relays on some generator set controls. Another simple technique is to use multiple transfer switches as close as possible to the loads, which will help coordinate the system with the right long time pick setting on circuit breakers upstream, allowing the branch circuit breakers downstream to instantaneously trip as close as possible to the fault without tripping other loads not affected by the fault.
