Hi All,


Hope you all are safe.

Our energy model analyst facing issues for one of our projects to meet the energy modeling compliance under LEED v4.1. The proposed project is designed with air cooled chiller and baseline HVAC system is water-cooled chiller.

The % improved beyond code should be calculated based on the following formulas.

1. Performance Cost Index = Proposed Building Performance/ Base Building Performance

2. Performance Cost Index Target = ((BBEUC+(BPF.BBREC))/BBP

3. % Improvement Beyond Code = 100 * (PCI Target - PCI)/PCI Target

From the above it is understood that, the Building performance Factor (BBF) is playing vital role to estimate the energy performance of building.

As per Dubai climate zone & our project type, the BPF factor is 0.62. So, our proposed building energy consumption is too much higher than baseline energy. Even considering the water-cooled chiller in proposed case, the project is unbale to meet the minimum energy savings.

To overcome the issues mentioned above, our team has decided to meet only the minimum energy performance with air cooled chiller by following Section 11 Energy Cost Budget Method.

Q1. I hope that the above approach is acceptable and just a positive energy saving is enough to comply. Is this correct?

Q2. The proposed chiller is air cooled chiller & heating is electrical resistance. So, the baseline system will be system 03 or system 08 or system 09.  Is this correct?

Q3. Whether COP of proposed chiller must be higher than baseline COP of system 03 or system 08 or system 09.


Q4. Whether COP of proposed chiller must be higher than baseline COP mentioned in Table 6.8.1-3

your support is highly help us to move further.

Thanks in advance.