Code Cycle: 2019 Standards Only!
The CEC incorporated the VCHP algorithms described into the Alternative Calculation Method (ACM), and the residential California Building Energy Code Compliance (CBECC-Res) performance compliance software, for use for demonstrating compliance with the Performance Standards specified in Title 24 Part 6, section 150.1(b). The CEC also approves that field verification procedures, as detailed in Appendix B, be authorized, in accordance with the requirements in Standards section 10-109(h), for use for determining compliance with Title 24, Part 6, and the eligibility requirements of this proposed VCHP performance compliance option.
General Description of the Algorithm Approach:
- Credit for cooling 5 percent as compared to a single speed SEER 14 / EER 11.7 system.
- Credit for heating 12 percent as compared to a single speed HSPF 8.2 system.
- Also assume additional energy use for ducted systems due to continuous fan operation equal to 50 W per ton of nominal cooling capacity. This additional fan energy use will be incurred during each hour where there is no cooling load during cooling season, or heating load during heating season unless the system is from a manufacturer who has certified to the Energy Commission that the applicable combination of outdoor unit and indoor unit(s) does not operate the indoor fan(s) continuously by default.
1. The performance compliance credit is applicable only to these system types:
- Ducted mini and multi split VCHP systems with low-static indoor units (low-static as defined by 10 CFR Parts 429 and 430, Docket No. EERE–2016–BT–TP–0029, Federal Register Vol. 82, No. 3, January 5, 2017).
- Mini and multi-split VCHP systems with ductless indoor units.
2. Dwelling units shall be provided with heating and cooling supply airflow in each habitable room by use of a ductless VCHP indoor unit located in the room, or by use of ducts connected directly to the supply air outlet of a ducted VCHP indoor unit. Transfer fans do not meet this requirement.
3. All ducts, ducted indoor units, and ductless indoor units must be located entirely in conditioned space.
4. New ducted systems shall provide a minimum of 350 cfm/ton of nominal cooling capacity (300 cfm/ton for altered systems complying with refrigerant charge verification).
5. All VCHP indoor units serving zones larger than 150 square feet shall be controlled by external wall mounted thermostats located within the zone served.
6. The manufacturer of ducted indoor units shall certify to the Energy Commission that the system is a VCHP that meets the definition of a low-static system as defined in the new DOE rule adopted January 5, 2017. The manufacturer's model number(s) shall be included in listings of certified-to-the-Energy Commission low-static pressure VCHP systems which will be published on the Energy Commission's website
7. The manufacturer may certify to the Energy Commission that their ducted indoor unit + outdoor unit combination does not operate the fan continuously by default. This certification is required in order to receive credit for non-continuous fan operation.
8. Air filter sizing shall be required for all ducted systems, regardless of duct length. The maximum allowable clean filter pressure drop for the required MERV 13 air filters shall be 0.1 inch wc..
9. It must be possible for a HERS Rater to view the manufacturer indoor unit and outdoor unit make/model/serial number in the field-installed unit in order to comply with the required field verification's.
See attachment below for Appendix A (Comparison with Standard Design Heat Pump)