Energy Savings from the Modification of Standard Commercial Freezer Temperature Set-Points
- Average of 10-12% electricity savings from 3°C temperature adjustment
- No food safety issues
- Food quality not impacted
- Created opportunity for successful policy change in Ontario regarding standard freezer set-points
- Savings for business, reduction in GHG emissions, reduction in peak electricity demand
Ontario’s food industry regulations, set by the Ministry of Health and Long-Term Care, dictates that frozen foods held by commercial establishments must be stored at a temperature of -18 degrees Celsius or lower. Considering that frozen food poses no safety risk, the modern cold chain system (ie. the production, freezing, storage, and transportation of food) is much improved, and commercial establishments are holding food for shorter periods, this freezer temperature set-point was found to be lower than necessary.
In late 2014, James Alden of Brickworks Communications, a leader in the energy efficiency industry, wrote an opinion piece for Business Energy Magazine, titled “Frozen is Frozen: Why Freezer Temperature Standards Need Re-examining”. In this piece, he postulated that the current temperature set-point policy could be modified, offering savings for business, energy benefits, and significant GHG reductions. The idea was supported by the American Frozen Food Institute. In 2016, Alden brought together a group of partners based in Toronto, including the Ontario Restaurant, Hotel and Motel Association (ORHMA) and Toronto Public Health, with supporters including Toronto Hydro and TAF. Alden raised money through the Conservation Fund of the Independent Electricity System Operator (IESO) to conduct field tests in the City of Toronto, in order to assess the energy savings and food quality impact of adjusting a commercial freezer’s internal temperature from -18°C to -15°C.
The study was developed and conducted by Alden with the support of NSF International and Finn Projects, who were contracted to conduct the in-field and 3rd party research.
An in-field research project was conducted which measured temperature and energy usage in 30 commercial freezers throughout Toronto. In addition, the study included an analysis of 3rd party literature assessing the impact of freezer temperature adjustments on food safety and quality. Two separate surveys were also conducted of field test participants and of companies which operate businesses along the cold chain. The final results include both information from the field tests as well as the survey information.
The results of the study suggested that a 3 degree Celsius temperature modification in Ontario’s freezer temperature set-point would offer measurable energy savings with no impact on food safety and limited risks to food quality for businesses. As a result of this work, and lobbying by ORHMA, a new Ontario regulation is to be enacted on July 1st, 2018 by The Ministry of Health and Long Term Care, removing the specific temperature requirement and simply requiring that food be kept in a frozen state while stored. This will allow business owners considerably more flexibility on the temperature set-point their frozen food can be stored at.
The freezer analysis project measured a total of 30 commercial freezers throughout Toronto. The analysis took place in three phases of eight weeks each, with ten freezers being metered during each stage. Phase 1 ran from May 2 to June 30, 2017, Phase 2 ran from July 7 to September 5, 2017, and Phase 3 ran from September 15 to November 17, 2017. The chosen freezers varied in size and use, from small chest freezers to large walk-in freezers used regularly in restaurants.
In each phase, electricity meters were installed on each freezer to record the electricity consumption once every 60 minutes. Two temperature loggers were then installed in each freezer to record internal temperature every 30 minutes. Two temperature loggers were installed outside each freezer to record the ambient temperature at the same intervals.
After four weeks of metering, the temperature set-point of each freezer was adjusted three degrees warmer, from -18°C to -15°C. After an additional four weeks, the metering equipment was removed from the freezers and the freezer temperature set-point was returned to -18°C. Of the 30 freezers planned for use in the in-field research, only 28 were used in the final analysis. This was due to one freezer undergoing service and one freezer malfunctioning, invalidating the freezer measurements in both cases.
The preliminary results of the project showed a non-weighted average individual energy savings of 9.1% per freezer. However, these figures do not factor in the effect of changes in ambient air temperature surrounding the freezer compressors on the units’ electricity consumption. The freezers used in this study averaged a temperature increase of 2.2°C, from pre to post-test periods below the target adjustment of 3°C.
The freezers demonstrated the greatest energy savings in phase 3, when the ambient temperature decreased on average by 3°C, and the least energy savings in phase 1, when the ambient temperature increased on average by 1.4°C. This suggests, as expected, that ambient temperature does have an influence on freezer energy usage.
Linear regression analysis and the post-adjustment ambient temperature data was used to calculate the adjusted energy consumption for each freezer. The goal was to take into account the effect of ambient temperature. The adjusted electricity savings over the course of the project totalled 7.4% weighted, or a non-weighted average electricity savings of 10% per freezer.
It is also expected that with a more accurate temperature adjustment, an average internal temperature increase of 3°C instead of 2.2°C would result in higher energy savings per freezer, near 10% weighted and above 12% unweighted.
A Case Study was written about the results of the project and can be downloaded here.
Following each phase of the in-field research, a survey was administered to the business owners whose freezers had been used in the testing process. The goal of these surveys was to determine if any problems or food quality issues arose as a result of the freezer temperature adjustment. For the majority of the respondents, frozen food is only stored for a 1-2 week period. Business owners have little desire to hold food for long periods of time, for cash flow, food quality, and freezer space reasons. Two respondents, a corner store and a small grocer, suggested some food could be in their freezers for as long as two months.
The 7-question survey was administered to 30 respondents, all of whom responded. In all cases, the business owners reported no impact on the quality of their frozen food following the temperature adjustment, and expressed no concerns about the possibility of the standard temperature freezer set-point being modified to -15°C.
A separate survey was also administered to manufacturing, storage, and retail companies which operate along the frozen food cold chain. The goal of this survey was to assess the possibility of any food quality issues emerging as a result of raising freezer temperatures.
The 11-question survey was administered via email to 30 company representatives, with a total of 19 individuals choosing to respond. The survey responses indicated that a temperature modification to -15°C may not be suitable for manufacturing and storage companies, as they sometimes store frozen food for 6 months or longer. The responses also showed that food is held for considerably less time by retailers and restaurants, making the proposed adjustment an appropriate fit for those settings.
The majority of the respondents (73.33%) supported a change in regulation pertaining to frozen food storage temperature, expressing that the temperature set-point should be raised to -15°C or higher.
FOOD SAFETY AND QUALITY
Food safety and quality was treated as a primary concern and focus in this study, with experts from NSF International conducting a detailed review of literature on time/temperature tolerance studies. In addition, business owners involved in the field research and individuals representing different parts of the cold chain were surveyed regarding their views and concerns about a change in the standard freezer temperature set-point.
Based on the in-field research results and participant survey responses, the policy change to freezer temperature adjustment should not be considered a concern from a food safety standpoint. Bacteria are inert when frozen, so food can be stored for consumption equally safely at any temperature below 0°C as it can at -18°C.
From a food quality perspective, there can be issues (color, texture, etc.) when food is held at warmer freezing temperatures for longer periods of time. Most businesses are holding food for 1-2 weeks, so this is not an issue in most cases. However, it is recognized that commercial establishments will need to balance energy savings and food quality based on the length of time frozen food is stored and the types of food being stored.
In some cases, such as in frozen food warehouses, frozen food is being stored for a particularly long time, for six months or greater. Further examination would be needed to determine if greater temperature flexibility is appropriate for businesses upstream on the cold chain.
The results of this study supported a successful call for Ontario to adjust its standard commercial freezer temperature set-point from -18°C to -15°C or higher for commercial end-users (restaurants, bakeries, schools, hotels, etc.). This 3 degree temperature adjustment alone offers between 10 and 12% electricity savings per commercial freezer, reducing costs as well as greenhouse gas emissions.
In addition, with this policy change, local utilities and the Independent Electricity System Operator (IESO) will see a direct benefit from the reduction of electricity use during peak summer months. This adjustment will not impact frozen food safety, and food quality issues should be able to be managed appropriately by businesses, given the short length of time food is kept frozen by the end user.
A new Ontario regulation has been registered and will be enacted on July 1st, 2018. The new policy removes reference to the specific temperature requirement of -18°C, requiring instead that “Food that is intended to be distributed, maintained, stored, transported, displayed, sold or offered for sale in a frozen state shall be kept in a frozen state until sold or prepared for use.”
Based on these results, it is also recommended that Ontario review additional energy saving opportunities for temperature management along the frozen food cold chain, and in residential freezers, which could be pre-set at a slightly warmer temperature. This research also offers a strong basis for other jurisdictions in Canada and the United States to examine this policy change and other similar opportunities.
For more detailed information about the methodology, results, surveys, and conclusions of this study, please contact James Alden using this form.