HVAC System 5 (VAV) - No Cooling

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Hi Hap Users,

I am modeling a parking garage and some MEP spaces that are serving a church and retail areas so I am using system 5. The parking garage and the MEP spaces are only heated but per ASHRAE 90.1 Appendix G I have to model the spaces being cooled too; here what I did and I would like if I get some confirmation from some experts on this method;

1- Under System Components: I unchecked the Schedule (J-D) for the Central Cooling Data
2- Under Zone Components: I changed the Cooling T-setpoints to be so high (ex 90) to avoid any cooling.

Beside that; would you recommend lowering the "Supply Temp." for the Central Cooling Data to the lowest possible input (35)? It would make more sense to push it all the way up (Max would be 1F less than Cooling T-setpoint; 89F in my situation).

Any input would be highly appreciated.

Regards,
Khaled Fouda

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HI,
Let me start off by saying I may not be what you consider an "expert" but have completed several submissions to LEED over the past few years, and I am assuming that is why you are modeling this building. Without knowing the square footage it is hard to determine if that is the correct baseline system. There are exception to the baseline systems that may be beneficial for you to entertain, G3.1.1 has the list. There are specific requirements outlined for the baseline cooling systems that must be followed, G3.1.3 which includes an air temp reset schedule. You must also remember that whatever you chose to model for cooling in the baseline must be modeled identically for the proposed system if the space is not cooled.

Thank you,
Matthew J. Baron, PE

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Wendel, Centerpointe Corporate Park, 375 Essjay Road, Suite 200, Williamsville, NY 14221
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Matthew Baron's picture
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HI,
Yes you should show the cooling load, it will impact savings slightly as you increase both baseline and proposed by the same amount in kwh. Modeling the unit with the required economizer and temp reset will obviously minimize this amount.

Thank you,
Matthew J. Baron, PE

[cid:image004.png at 01D167C7.E28B7C40]
Wendel, Centerpointe Corporate Park, 375 Essjay Road, Suite 200, Williamsville, NY 14221
p. 716.688.0766 tf. 877.293.6335 e. mbaron at wendelcompanies.com w. wendelcompanies.com

architecture | engineering | planning | energy efficiency | construction management

CONFIDENTIALITY NOTICE: This email transmission is confidential and is intended only for the person(s) named above. Its contents may also be protected by privilege, and all rights to privilege are expressly claimed and not waived. Any unlicensed distribution, copying or disclosure of this email is strictly prohibited.

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