Chiller Selection Tool During the Design Stage

Chiller plant systems use 30% to 60% of a building’s total energy consumption, hence it’s important to ensure that chiller plants are designed optimally. 

Engineering teams design chiller plant systems based on a cooling load profile, that is affected by occupancy and the activity profile of the building. The chiller plant system will iterate with different combinations of chillers and their accompanying components due to different chiller cooling capacity, brands and staging configuration to obtain the most energy efficient chiller plant system. 
 
The chiller plant system efficiency varies based on many factors. See Annex A for a typical workflow of the design process, as well as a list of variables which may affect the chiller plant system efficiency.
 

Challenges

Typically, the iterative selection process is done on Excel. However, due to the large number of variables affecting chiller plant performance, there is a limitation on the number of chiller configurations (~3 to 5) considered during design stage. This results in sub-optimal chiller plant equipment selection.

Many of the variables affecting chiller plant efficiency are chiller dependent. Correspondingly, chillers are the largest determinant of chiller plant system performance: 

Chiller size and brand:

• The first iteration is often based on the designer’s experience or supplier recommendation. From there, subsequent fine-tuning is carried out. Probable and effective chiller configurations may be missed out.
• Supplier input is required for each subsequent design iteration, which is a time-consuming process as well.

Chiller staging:

• This is often done manually for each chiller configuration, and the process is repeated for different chiller brands. This process is time consuming, and often subject to human error, such as unoptimized chiller staging, mistakes in interpolation, etc.

The solution¹ should come with following features:

Baseline data²

1.    Provide baselines based on the chiller brand, type, e.g. screw, centrifugal, magnetic bearing etc, and size.
 

Building and system requirement (design input)

2.    Allow the designer to input the building cooling load for each project on an hourly basis, 
3.    To indicate the required Green Mark requirements to achieve desired level of certification, and 
4.    To calculate the chiller plant system efficiency based on the building cooling load and baseline data performance
 
Design optimization and baseline data update
5.    Iterate and propose the top 3 chiller configurations based on the provided building cooling load, so that the designers can request for the relevant technical data sheets from the product suppliers with high confidence base on the above steps.
6.    User input technical specifications of NEW³ chiller plant components (chillers, chilled water pumps, condenser water pumps, cooling towers).
7.    Calculate the chiller plant system efficiency based on the building cooling load and user inputs from the NEW technical data sheets from the product suppliers
8.    Conduct a Life Cycle Cost (LCC) analysis to evaluate and select the “best” configuration for the designer’s consideration.
9.    Store a database of chiller plant components (chillers, chilled water pumps, condenser water pumps, cooling tower) based on technical data sheets from chiller suppliers 
10.    Store different iterations of chiller configurations for projects, for comparison

Refer to indicative desired solution flow chart in Annex B.

Note:

¹ The developed tool will be provided to JTC for user testing.
² Carry out a study on the existing chiller plant components (chiller, chilled water pumps, condenser water pumps and cooling towers) available in the market and provide a baseline for these products. The baseline study of chiller plant components should encompass at least 3 brands per component.
³ Allow user to add in new technical specification for the chilled water system equipment into the tool.

The envisioned solution’s workflow from a chiller plant designer’s perspective will be:

1. Manpower productivity & carbon savings - based on the solution’s database of existing chiller plant components in the market, to propose energy efficient chiller plant configurations.

2. Manpower productivity - using these proposed chiller plant recommendations to seek technical data sheets from the suppliers.

3. Manpower productivity & carbon savings - based on the suppliers’ response, the user will input data into the software to iterate different proposals for comparison.

The successfully developed solution will significantly improve manpower productivity for JTC’s chiller plant designers and reduce the operating carbon footprint of JTC’s industrial estates.

• Plug-ins to existing Environmental Sustainable Design (ESD) software, such as Integrated Environment Solutions
• Brand new software package (Preferred)
• Exclude: Product brand specific calculators, such as Carrier’s E20.

To be kept within 12 months

Evaluation Criteria

• Time to implementation; Impact factor.
• Price (40%): Value-for-money; level of co-funding.
• Quality (60%): Proposal’s scope of work; Operational feasibility for deployment at the targeted Estate or Facility; Minimal/no nuisance and disruption to operations and/or tenants; Cost benefit analysis; Relevant experiences required to develop and deploy; Commercialisation and/or Implementation plans.

Testbed/Trial Site

Based on the proposed solution and existing project timelines, the solution might be tested with projects in design phase and/or retrospectively tested on recently designed JTC projects to verify the optimisation process.

Payment Model

Fixed price, payment by milestones

Video of Briefing

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