VRV and ASHRAE 90.1-2007 and 189.1 Standards

Sonia M. Miranda Palacios

RA / LEED AP BD+C / QCxP

cota.CERO

LEEDuser Basic Member

9 thumbs up

March 22, 2013

Hi all. I´m working in a project with VRV and want to specify a system with high COP values, and three issues surfaced.... 1- Since there is no exact system specified in the ASHRAE 90.1 that matches the VRV system, I have been told to model the VRV system using the efficiencies in Table 6.8.1B. However these efficiencies are typically for full load operations, so it will not capture the advantage of the part load capability of the VRV systems. Therefore, the savings calculated will be typically conservative. 2- Can I compare a VRV with the effciency of a chilled water system? 3- Or do you think it is a good idea to at least use Table C-2 values from ASHRAE 189.1-2009, with higher COP values? I want to include minimum COP values within the technical specifications. We are just indicating system size, capacity, etc, and no brands / models. Therefore, we want to make sure we get a system with high energy efficiency values. Any thoughts?

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Jorge Torres-Coto

Building Systems Commissioning Engineer

Empirical Engineering, LLC

LEEDuser Basic Member

14 thumbs up

Fri, 03/22/2013 - 15:05

Sonia the following answers apply to your questions as follows: 1.Depending on the software you are utilizing you can model (for your DESIGN CASE) a VRV system adequately with or without "fixes". The followinng links may help you with eQUEST and/or energy plus. Energy Pro, which is used in California has VRV libraries included. http://www.google.com.mx/#hl=es-419&sclient=psy-ab&q=energy+plus+vrv+system&oq=energy+plus+vrv&gs_l=hp.1.0.0i30j0i8i10i30.4309.19737.0.23369.15.14.0.1.1.1.1045.4099.2-2j4j1j0j1j1.9.0...0.0...1c.1.7.psy-ab.v8XiNmBdIHs&pbx=1&bav=on.2,or.r_qf.&bvm=bv.44158598,d.b2I&fp=f06a09c846aeaaee&biw=1366&bih=622 http://www.google.com.mx/webhp?hl=es-419&tab=ww#hl=es-419&sclient=psy-ab&q=equest+vrv&oq=equest+vrv&gs_l=hp.3..0i30l2j0i8i30.2537.5526.0.7138.10.9.0.0.0.1.2329.5962.2-1j1j3j8-1j1.7.0...0.0...1c.1.7.psy-ab.l3pzbpq9AQE&pbx=1&bav=on.2,or.r_qf.&bvm=bv.44158598,d.b2I&fp=f06a09c846aeaaee&biw=1366&bih=622 In short you end up modeling a Heat Pump system with a custom performance curve, sounds simple but does equate into some effort. 2.When you are referring to comparing I am assuming you are performing LEED calculations, if so you have to compare to the BASELINE definition in ASHRAE 90.1 Appendix G table G3.1 3.

Robert Sutton

P.E., C.E.M, President/Owner

Sutton Engineered Systems, Inc.

LEEDuser Basic Member

0 thumbs up

Fri, 03/22/2013 - 15:11

I am told Trace 700 runs VRV/VRF systems and two manufacturers have data to assist with setting it up in Trace and another in EPro Plus.

Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Fri, 03/22/2013 - 16:01

Guidance on the minimum efficiencies for VRV systems can be found in ASHRAE 90.1-2010.

Sonia M. Miranda Palacios

RA / LEED AP BD+C / QCxP

cota.CERO

LEEDuser Basic Member

9 thumbs up

Mon, 03/25/2013 - 18:20

Thanks Guys!. Jorge and Robert, we are definitely doing a energy simulation using Trace and Energy Pro (who does VRV modeling). We want to see how the same building compares...For know I just wanted to have an idea on COP values, botn minimum and "more efficient". I also checked the ASHRAE 189.1 standard and Marcus, thanks for the info regarding ASHRAE 90.1 2010.