SOME OUTSTANDING TITLE 24 ISSUES FOR文档格式.docx

1、 HIGH-RISE RESIDENTIAL SHGC REQUIREMENTS & HEATING ENERGY: The 2001 Standards adopted relatively low SHGCs for High-Rise Residential buildings, even in coastal climate zones. A more rigorous analysis should be performed to see whether these low SHGCs actually produce buildings with lower energy use

2、than buildings with more moderate SHGCs, that would receive more beneficial solar heat gain in winter （thus lowering heating energy use）. SHGC REQUIREMENTS AND PERFORMANCE COMPLIANCE: The 2001 Standards reduced the allowed SHGC requirements for all building types. When the prescriptive standard has

3、a low SHGC requirement, as it now does, performance compliance need to be rigorously tested to determine whether the low SHGC requirement is causing the standards to be weakened when complying under the performance method. This could occur because the Standard Budget will assume a building with low

4、solar heat gain in winter. A proposed building with higher SHGC will have lower energy consumption in winter. VARY RESIDENTIAL SHGC REQUIREMENTS?: Consider adopting a higher SHGC requirement for multi-unit residential buildings that use a central heating system and have no cooling system. Because it

5、 is difficult to add mechanical cooling to such a building type when it has central heating, it is very likely that higher SHGC glass will save much more heating energy than it will cause an increase in cooling energy. LOW-RISE RESIDENTIAL FENESTRATION THERMAL EFFICIENCY: Reevaluate the fenestration

6、 U-Value requirement. Nonmetal frames and Low E glass prices have gone down since the previous economic evaluation of residential fenestration efficiency requirements. LOW-RISE RESIDENTIAL “STANDARD” WATER HEATER: Consider allowing tankless gas-fired water heaters with electronic ignition to meet th

7、e requirements of a “standard” system. If these systems are as energy-efficient as the manufacturers claim, Title 24 should not create an impediment to their use. Unless it imposes an energy penalty, allow any number of tankless systems （with electronic ignitions） per residence to meet the definitio

8、n of “standard” system （unless the system has recirculation）.In the RFQ for the a consultant for the 2003/2005 Standards, the CEC correctly points out that high-efficiency storage water heaters （40 and 50 gallons） cost about the same as low-efficiency water heaters, and therefore act to weaken the r

9、esidential standards. The RFQ suggests a possible remedy of requiring water heating energy requirements to be met independently of the space heating and cooling energy budget. While this remedy is definitely worth consideration, it would not produce an incentive to use tankless gas water heaters. Co

10、uld the ACM rules divorce the water heater energy from the space conditioning energy when a storage-type water heater is used, but continue the current practice of combining all energy when a tankless water heater is used? Or perhaps another type of incentive could be adopted to encourage use of tan

11、kless water heaters. NONRES WATER HEATING: Regulate nonresidential service hot water systems. Perhaps any gas-fired system should be acceptable. However, if an electric system is proposed, performance compliance would be required. The Standard water heater energy would be based on a gas-fired system

12、 of the same capacity. HEAT RECOVERY （Res and Nonres）: Require ventilation air heat recovery （e.g. air-to-air heat exchanger） in buildings or spaces with high OSA design （e.g. above 25% of HVAC system cfm）, and certain amount of operating hours （e.g. min. of 40/week）. Some residential buildings do h

13、ave high OSA requirements, like convalescent homes.INITIATIVES TO REDUCE PEAK COOLING LOADS: NONRES WEST GLAZING: Limit west facing glass area to 40% of the west Gross Wall Area （prescriptive approach）. Currently, the standards only limit overall glass areas. The performance budget would be based on

14、 the same requirement. RESIDENTIAL WEST GLAZING: Prescriptive Package compliance does not regulate west glass area. Consider a limit （perhaps 30 or 35% of total fenestration area?）. Note that under Performance compliance, there is modest regulation by orientation in that the allowed budget is based

15、on equal areas of fenestration in all four cardinal directions. RES & NONRES AC EFFICIENCY: Increase minimum efficiencies for air conditioning equipment. NONRES AC SIZING: Mandate maximum air conditioning sizing, based on prescribed loads analysis, for both Residential Prescriptive and Performance c

16、ompliance, and for Nonresidential Performance compliance approach （as is currently required under the Nonresidential Prescriptive approach）. NONRES EVAPORATIVE COOLING: Develop a compliance credit to encourage the use of evaporative coolers instead of conventional air conditioners. NONRES: To reduce

17、 the incidence of AC system oversizing, require that the cooling load calculation account for structural shading of the fenestration （e.g. overhangs, fixed awnings）.INITIATIVES TO REDUCE BOTH HEATING & COOLING LOADS: RES FENESTRATION AREA: Develop method for reducing the prescriptive fenestration ar

18、ea allowance for larger buildings （single-family as well as multi-family）. Under the current fenestration allowance approach, based solely on floor area, very small buildings are penalized, and larger buildings get an undue credit （i.e. there design fenestration area is usually lower than the prescr

19、iptive fenestration area allowance）. One possible remedy is to restructure the basic package glazing area allowance to reflect a combination of floor area and perimeter. APPENDIX A explains a proposal for a single formula to determine allowed fenestration area for all low-rise residential building t

20、ypes. This formula results in similar glazing allowances for average size homes as the current formula, reduces the allowed fenestration area of very large homes, and brings the glazing allowance of multi-unit buildings in line with actual design practice, without having to justify various formulas

21、for different sizes or types of residential buildings. RES MULTI-FAMILY PRESCRIPTIVE GLASS AREA: Should a restructuring of the fenestration allowance for all residential buildings, as suggested above, not be found acceptable, consider reducing the fenestration allowance for larger multi-family resid

22、ential buildings. I have found that larger multi-family buildings often have glass areas of around 10 to 13 percent of the C.F.A. The current Standards give multi-family buildings an unwarranted “credit” under performance compliance. Encourage heat and cool recovery from exhaust air to temper ventil

23、ation air （air-to-air heat exchanger）.MISCELLANEOUS NONRESIDENTIAL STANDARDS EFFICIENCY ISSUES: NONRESIDENTIAL PERFORMANCE REFERENCE HVAC SYSTEM: The selection of the reference HVAC system （used to determine the Standard Budget） should be based on the conditioned floor area, building volume, or a co

24、mbination of one of these factors and the number of stories, instead of basing it solely on the number of stories. There are many very large three story buildings, where a VAV reference system would be appropriate; conversely, some four story buildings may be very small, depending on their footprint

25、. One example of a very large three story building is the Moscone Center Addition. It is a three story building, with very high floor-to-ceiling distances. The performance compliance reference system was a single-zone constant volume type, but the building appropriately （for its volume） uses a built

26、-up VAV system. The Title 24 Standard Budget allowed a lighting LPD that is moderately higher than the prescriptive LPD. NONRESIDENTIAL SKYLIGHTS: Revisit curb modeling issue. To simplify skylight modeling, perhaps curbs should not be included in either the skylight or roof modeling. Instead, curbs

27、could either have a mandatory minimum insulation requirement, or the Nonresidential Manual could simply emphasize that all curbs must be modeled （the ENV-2 form could have a check box for curbs, as a reminder that they need to be modeled or meet a mandatory minimum insulation level） EXTEND NONRESIDE

28、NTIAL LIGHTING REQUIREMENTS to FOLLOWING OCCUPANCIES: Registered Historic buildings. I Occupancy buildings （excluding surgery rooms）. Buildings maintained outside the human comfort range. Unconditioned buildings. EXTEND NONRESIDENTIAL ENVELOPE REQUIREMENTS to FOLLOWING OCCUPANCIES: I Occupancy build

29、ings. NONRESIDENTIAL LIGHTING ELIMINATE “RETAIL” OCCUPANCY TYPE: Eliminate “Retail” from the list of building Type of Uses and Primary Function Areas. The use of the word “retail” in the Standards causes much compliance confusion, as it is used to justify retail lighting allowances for non-retail te

30、nants in so-called “retail buildings”. In place of “retail”, define both “Shopping Center Building” and “Merchandise Sales”. Shopping Center Building would be defined as a building that could be occupied by office-type operations, as well as by tenants providing services （such as realty and packagin

31、g） and tenants selling merchandise. Unleased space in Shopping Center Buildings would receive the same lighting power allotment as office space. Space leased for the purpose of Merchandise Sales would get an appropriately greater allotment. Typically, requiring unleased space to comply at an office level of lighting is not a hardship, for the following reasons: A） Many developers of “plain vanilla” retail space only install office-type lighting anyway; B） Retail tenants that move into “plain