HAP actual weather data entry

[ConServe2]

To HAP Users

We have a LEED project that requires monitoring and veirfication (M&V). The initial modeling calculatins were accomplished with HAP. But the M&V process may require use of ACTUAL hourly weather data for our location.

Is there a way to substitute the local "typical" TMY data supplied by Carrier with ACTUAL HOURLY TMY data?

OR Is there another program that is easier to work with than DOE2?

Thanks, Ken

 

[CarolinaPE]

I am pretty sure you can go to the city entered and enter actual design temps. We have a problem with our winter temps as they are about 30 degrees off what to expect for a low. It should be under weather properties and design temps. It looks pretty painful to enter hour by hour for each month though. I do not know of any other way.

 

[tombmech]

I think you are misinterpreting the intent. LEED grants a point for M&V as per IPMVP, International Performance Measurement and Verification Protocol - but it does not mean you re-calculate the loads with measured weather data.

That would be pointless, anyway. A load calculation is an estimate, nothing more. That estimate depends on seasonal factors such as sunlight radiation, wind, and precipitation. You cannot directly monitor for those factors and apply a specific load calculation. It's not relevant.

Quoting from the IPMVP, Volume 1, 4.9 Weather Data:
"4.9 Weather Data

Where monthly energy measurements are used, weather data should be recorded daily and matched to the actual energy metering period.

For monthly or daily analysis, government published weather data should be treated as the most accurate and verifiable. However, weather data from such sources may not be available as quickly as site monitored weather data.

When analyzing the response of energy use to weather in mathematical modeling, daily mean temperature data or degree days may be used.
"

What is relevant is Measurement & Verification of the systems you employ. Essentially, the entire LEED procedure is recognizing (sort of) the major failing in the old energy crisis days: Engineers would take credit up front for an energy-savings system, but then never go back and verify that it worked.

LEED mentions the following items:
* Lighting
* Constant and variable motor loads
* Variable Frequency Drive (VFD) operation
* Chiller efficiency at variable loads
* Cooling Load
* Air and water economizer and heat recovery cycles
* Air distribution static pressures and ventilation air volumes
* Boiler efficiencies
* Building specific process energy efficiency systems and equipment
* Indoor water risers and outdoor irrigation systems

Credits are taken for each of the above in determining the pre-construction energy-savings. The point of M&V is proving that those "assumptions" are valid.

In the case of verifying the "Cooling Load" for instance, you should meter the systems on peak days - the ASHRAE design temperatures, in other words. Does the actual percent of chiller loading correspond to the calculated load? Or - was the connected efficiency for the total chilled water system - chiller, pumps, cooling tower, etc. - the same as the efficiencies "assumed" in your HAP calculations?

The other items are similar - Static Pressures, for instance. Your HAP and load calculations assume certain losses for infiltration, duct pressure losses, etc., etc. So, what is the M&V for the fans and AHU's at rated flows - does it agree with the calculated "assumptions" for pressure losses and the resulting energy savings calculated?

Nowhere does it really imply that you should "do over" the entire hourly load calculations based on measured weather data.