Refrigerated Walk-In Coldrooms (WICs) are applied in a wide range of facilities as part of the delivery stream from food source to consumer. However, WICs aren’t regulated for minimum energy efficiency performance, making them difficult to assess. WICs can be more energy efficient, but what’s the best way to go about it?
- Increase the insulation?
- Increase the efficiency of the compressor motor fans & lights?
- Or reduce the amount of infiltration (air leakage)?
Dr Clyde Anderson and Certified Energy Efficiency Assessor Michael Anderson have written an in-depth report comparing the energy consumption between existing and proposed-design walk-in Coldrooms with various options applied.
It’s a great read, but if you’re short on time here’s a quick summary:
- There is a proposal from the Equipment Energy Efficiency Committee (E3) of the Australian and New Zealand Ministerial Council on Energy to regulate elemental parts of Walk-In Coldroom systems.
- Rudimentary thermal modelling was included in the proposed 10 year strategic Draft proposal “In From the Cold… ”.
- Manufacturers of insulation products — through the industry governing body “Expanded Polystyrene Panel Manufacturers Group” — are planning to make a submission to the Committee regarding the benefits of the proposed insulation increases.
- Our Report addresses only the proposed changes in minimum R-value insulation of wall, ceiling and floor panels. It shows that increasing insulation R-value will only slightly reduce the energy consumed in Walk-In Coldrooms.
- There are many transient heat loads that are part of operation of WICs that are difficult to include any energy efficiency regulation.
- Compared to steady-state (closed box) heat transfer, one important factor in the calculation of total kWh energy is the loss of cold air due to door opening (infiltration).
- Increasing only insulation will not achieve the expected overall benefits as the envelope heat transfer is only a small percentage of the total heat load.
- Infiltration should be addressed before increasing the R-values of Walk-In Coldroom envelopes, as this would give a more cost-effective energy reduction.
- A holistic, total system approach to efficiency certification of WICs is advocated since the incorrect application of efficient components can result in an inefficient design.
- Performance-based assessment under a National regulatory body like the Australian Building Codes Board, is appropriate for WICs.
Disclaimer: whilst the data in this Report is provided with reference to calculations and computer simulations, it is only as good as the information provided plus the assumptions used in the simulations and is generic in its recommendations. Naturally, this may not reflect your specific building or simulation scenario. Alternative data & assumptions, different building designs & building fabric will produce different simulation results. If you’re interested in optimisation for your specific building, we offer full Commercial Energy Efficiency Assessments as well as thermal simulation consulting. Contact us for more information.