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HomeMy WebLinkAboutENERGY CONSERVATION IN LDGS - 06-91 - SUBMITTAL DOCUMENTS - ROUND 1 - Staff's Project Comments � r' Utility � vices Light and Power City of Fort Collins MEMO DT: 11 February 1991 TO: Sherry Albertson-Clark, Planning A`5 ..w cz FM: Doug Swartz, Denms Sumner, Light and Power RE: Draft LDGS Commercial Energy Conservation Points We applaud the intent of this project, as presented in the mission statement on page 3: "to establish clear standards to use in evaluating and awarding energy conservation points for non-residential planned unit developments." The key word here is "clear" -- we question whether that has been achieved. What is proposed has many ambiguities and room for interpretation. At our meeting with you on January 23, we raised a number of issues related to this. We don't see these reflected in the current draft. To recap our concerns: Method 1: the performance option ■ The wording used to describe the required procedures is very vague. A consultant will be able to generate almost any answer he or she wishes for a given building, depending upon the modeling approaches and assumptions used. Unfortunately, having a Professional Engineer stamp the plans is little protection. At a minimum, there need to be some ground rules on procedures to follow and assumptions to use (e.g. certified software that is permitted, guidelines on occupancy, etc.). There need to be requirements that the calculations are submitted with adequate, standardized documentation. Finally, we recommend a provision that the calculations be re- viewed by someone representing the City, whether that be an employee or someone working on a contractual basis. ■ If the points are based on end use Btu's only, be aware that electric systems tend to use a small number of Btu's compared with gas systems, but electric Btu's are more expensive. ■ When must this method be used? Why wouldn't most projects choose to use the simpler Method 2? Method 2: the point approach ■ All point approaches suffer the same generic deficiency. If the building being proposed is different from the one that was modelled to generate the points, results 700 Wood Street • P.O. Box 580 • Fort Collins, CO 80522-0580 • (303) 221-6700 r �. will not be accurate. The statement on page 7 that "there is a correlation between points awarded on both methods" is really only true for the building that was modelled, and others that are quite similar in geometry, orientation, occupancy, etc. This is especially a problem with commercial applications that are so variable with regard to use. One way to improve accuracy with point methods is to have more than one base case building and a point chart for each one. ■ There is no documentation in the draft about what is required to earn any of the points. For example, item 27 "Motion detector lighting control is used" -- does one light in the building need to be controlled, or do all of them? For item 4, how will the passive solar savings fraction of 0.4 be documented? For item 34, what does the computerized energy management system control? Similar questions could be raised about most items on the list. ■ Page 7 states that points may be combined in an additive fashion. This will be inaccurate for many combinations. ■ Will Method 2 points be updated as energy code changes? The current point chart will be even less accurate with future code changes. We have reservations about the current proposal. It seems to be wide open to "gaming" the system in order to gain points. It may be a step forward from the current system which has even larger ambiguities, but we question whether the modified LDGS will really make much difference in the level of energy efficiency of what is being built. Again, we do applaud your efforts to achieve the important community objectives of conserving energy. The commercial sector offers many opportunities for improvement, and is particularly important because the developers/builders often are not the eventual bill payers. Their priority is keeping first costs low -- they have Iittle incentive to be concerned with long term operating expenses such as energy costs. LDGS incentives can have a real and meaningful impact on this problem. We encourage you to commit the resources needed to ensure that the potential of your effort is fully realized.