Summary

Demand-Controlled Ventilation for Commercial Kitchens

Commercial Kitchen Ventilation: Variable Speed Based on Heat and Smoke vs. Constant Speed Operation During Occupancy

A system for commercial kitchen exhaust fans that uses smoke and heat sensors to control the exhaust hood airflow and make-up air volume based on cooking activities.

Synopsis:

The Consortium for Energy Efficiency (CEE) indicates that with demand-controlled kitchen ventilation (DCKV), energy savings from kitchen supply and exhaust fans can be as much as 70%. While the energy savings are impressive, less than 1% of commercial kitchen ventilation systems have demand control. According to the American Gas Association and the U.S. Department of Energy (DOE), commercial kitchen exhaust fans in the 1 million food-service establishments in the U.S. and Canada waste more than $2 billion in energy costs each year while exhausting 3 billion cubic feet per minute (cfm) of airflow. The main problem is excess ventilation. Most exhaust fans run at constant speeds – even when the cooking equipment is idle. By contrast, demand ventilation systems vary the amount of ventilation air to more closely match the actual ventilation requirements.

Ventilation systems are integral for a safe and comfortable kitchen environment. DCKV equipment maintains comfort and indoor air quality by varying the speed of the exhaust and supply fans based on cooking activity. The DCKV system obtains continuous inputs from occupancy, temperature, and/or infrared sensors, as well as data about the amount of smoke present. Variable frequency drives (VFDs) are used to automatically adjust the amount of exhaust and ventilation airflow to meet actual requirements. Potential benefits include:

Fan energy savings of 30% to 70%.
Significant space heating and cooling energy savings.
Improved comfort for kitchen employees because of reduced noise and reduced volumes of hot, cold, or humid make-up air during idle cooking periods.
Improved fire safety because the exhaust air temperature is monitored. If the temperature approaches the fusible link temperature of the fire suppression system, an alarm sounds and/or cooking appliances are turned off. With lower air velocities, grease capture is better, which also improves fire safety.
Improved indoor air quality because CO₂ levels in the dining area can also be monitored. The exhaust and outside air levels can be adjusted to 100% if the CO₂ level exceeds a specified setting.

Energy Savings: 57%

Energy Savings Rating: Approved Measure What's this?

Level	Status	Description
1	Concept not validated	Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.
2	Concept validated:	An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.
3	Limited assessment	An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline.
4	Extensive assessment	Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions.
5	Comprehensive analysis	Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.
6	Approved measure	Protocols for technology application are established and approved.

Simple Payback, New Construction (years): 5.3 What's this?

Simple Payback, Retrofit (years): 6.3 What's this?

Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:

Simple Payback = Incremental First Cost / Annual Savings

The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.

For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.

For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.

Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.

The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.

Details

Demand-Controlled Ventilation for Commercial Kitchens

Commercial Kitchen Ventilation: Variable Speed Based on Heat and Smoke vs. Constant Speed Operation During Occupancy

A system for commercial kitchen exhaust fans that uses smoke and heat sensors to control the exhaust hood airflow and make-up air volume based on cooking activities.

Item ID: 155

Sector: Commercial

Energy System: HVAC--Sensors & Controls

Technical Advisory Group: 2009 HVAC TAG (#2)

Technical Advisory Group: 2015-1 Commercial HVAC TAG (#11)
Average TAG Rating: 3.5 out of 5
TAG Ranking Date: 03/10/2015
TAG Rating Commentary:

I'm not clear on how this is emerging technology. It's already code in large kitchens and is in many programs already. We have found it not cost effective in small applications.
BPA already has this measure, but there has been very little uptake. There are maintenance issues which can shut down a restaurant, and there are no non-energy benefits to counteract the maintenance issues.
We already have a measure, but could use program help.
I am not aware of case studies demonstrating savings, but believe the concept to be sound, a real market need, and would have some ease of implementation. Persistence of savings and maintenance issues may be present.
My reservation is only that each installation will require a fairly sophisticated contractor to design and install, i.e, there is significant engineering time involved. This may make savings evaluation more challenging - but heck, this is like any other system.
This one seems to be being pushed a lot by vendors. It makes sense, but I'm not sure it can be deemed.
The technology in tests performs but there is little market uptake -- don't know if it is emerging because it is already in our programs
This is required by CA Title 24 code for systems over 5,000cfm -- and ASHRAE. The SPEED program and the CA FoodService Technology Center have lots of case studies.
Code requirements exist for new projects with minimum hp requirement; may be good application for existing buildings.

Synopsis:

Fan energy savings of 30% to 70%.
Significant space heating and cooling energy savings.
Improved comfort for kitchen employees because of reduced noise and reduced volumes of hot, cold, or humid make-up air during idle cooking periods.
Improved fire safety because the exhaust air temperature is monitored. If the temperature approaches the fusible link temperature of the fire suppression system, an alarm sounds and/or cooking appliances are turned off. With lower air velocities, grease capture is better, which also improves fire safety.
Improved indoor air quality because CO₂ levels in the dining area can also be monitored. The exhaust and outside air levels can be adjusted to 100% if the CO₂ level exceeds a specified setting.

Baseline Example:

Baseline Description: 3 hp Constant Speed Exhaust Fan for Commercial Kitchen Hood
Baseline Energy Use: 18520 kWh per year per unit

Comments:

For a single 3 hp exhaust fan drive motor, the baseline input power is 2,200 watts multiplied by a 75% load divided by an efficiency of 87% at the 75% load point. The average weekly hours of operation for restaurants is 92.6 (from Table C-SC2 of the 2009 NEEA "Commercial Building Stock Assessment"), yielding about 4,800 annual operating hours. Assuming 4,800 hours of operation per year, the energy use for a baseline 3 hp kitchen exhaust fan is 9,260 kWh/yr. This annual energy use will be doubled to account for makeup air fan requirements.

Manufacturer's Energy Savings Claims:

Comments:

The CEE has developed a field test protocol for DCKV savings verification studies. They have also worked with manufacturers to gather a credible body of evidence (field test reports) and operate a clearinghouse demonstrating the benefits of DCKV. The CEC indicates that fan energy savings can be as much as 70%. Space heating energy savings also occur, resulting in cost savings that might exceed the cost savings from fan energy savings. A field study at a full-service restaurant found fan energy savings of 10,000 kWh/year (valued at $800) and heating savings equivalent to 1100 therms/year of natural gas (valued at $1,000) (from: CEE ‘Commercial Kitchen DCV Reports', (CEE, 2015).

Best Estimate of Energy Savings:

"Typical" Savings: 57%
Low and High Energy Savings: 37% to 70%
Energy Savings Reliability: 6 - Approved Measure

Comments:

The National Fire Prevention Association (NFPA) standards require that an exhaust hood operate at full design airflow whenever cooking activities occur under the exhaust hood. But cooking equipment is not used all at once or all of the time. Typical restaurants have a mealtime rush and low occupancy between peak periods. However, the kitchen hood exhaust and make-up air systems must be designed for the maximum load under each hood and are traditionally equipped with on/off controls, meaning that they operate constantly over the day. Energy savings are available due to system oversizing and operating schedule (EPA, 2013). The potential for energy savings is estimated by assuming the exhaust fans can run at 50% of full speed about 50% of the time (and at full speed for the remainder of the time). A fan that operates at 50% of rated speed provides about 50% of rated airflow. With this operating regime, the fan would use about 0.5 + 0.5 x (0.5)³ or 56.25% of its baseline energy use. Expected energy savings are 43.75%.

Pacific Gas and Electric (PG&E) conducted a number of DCKV case studies in California at a variety of sites, including an institutional cafeteria, a casual dining restaurant, a hotel main kitchen, supermarket, campus dining facility, and several quick-service restaurants. The average exhaust fan speed reduction was 26%, accounting for an average total fan power reduction of 57% (U.S. DOE, 2013).

A PG&E case study at the Mark Hopkins Hotel found an average exhaust and makeup fan power reduction of 62.1%. Due to variations in kitchen design and operating patterns as well as local climate, savings vary for each installation (EPA, 2013).

In addition to the fan power energy savings noted above, savings result from reduced heating and cooling loads. In a commercial kitchen, these are primarily cooling loads, which are difficult to estimate. The cooling system serving a kitchen may also serve the dining room and other spaces; it may not have heat recovery ventilators; and savings will vary significantly with climate, infiltration, and airflow between the kitchen and dining room. More data is needed to fully understand the impact on kitchen cooling loads; therefore, our estimate of total energy savings is the lower of the two in the studies referenced above and should be taken as conservative because it does not reflect cooling energy savings.

Energy Use of Emerging Technology:

7,963.6 kWh per unit per year What's this?

Energy Use of an Emerging Technology is based upon the following algorithm.

Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))

Technical Potential:
Units: unit
Potential number of units replaced by this technology: 64,400
Comments:

According to a Navigant report for the Energy Information Administration (EIA), the estimated installed base of commercial kitchen hoods in 2015 in the U.S. is projected to be 810,000. Because the Northwest has a population that equals roughly 4% of the total U.S. population, an estimated 32,400 commercial kitchen hoods are located in the region. The percentage of hoods that are already equipped with demand-controlled ventilation is small. The U.S. DOE reports that an installed base of about 10,000 DCKV systems has been installed over the past 25 years. Assuming there are just two exhaust hoods per kitchen, an estimated 64,400 exhaust hoods are candidates for upgrading in the Northwest.

Regional Technical Potential:
0.68 TWh per year
78 aMW
What's this?

Regional Technical Potential of an Emerging Technology is calculated as follows:

Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)

First Cost:

Installed first cost per: unit
Emerging Technology Unit Cost (Equipment Only): $6000.00
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $0.00
Baseline Technology Unit Cost (Equipment Only): $1000.00

Comments:

The installed cost for new construction is $6,000 for 3 to 8 total controlled horsepower (hp). This information was taken from the publication, “Demand Control Ventilation for Commercial Kitchen Hoods” (SCE, 2009) by Southern California Edison, and includes hood costs. For retrofit applications in a hotel, the cost can range from $20,000 to $40,000 for 30 to 35 total controlled hp. Quick-service restaurants may have retrofit costs between $8,000 and $15,000 (EPA, 2013). Note that the supply of ventilation air must be varied in accordance with the quantity of air exhausted. Energy savings (electrical or gas) may also accrue from reducing the amount of conditioned air exhausted from the kitchen.

The actual equipment cost depends on the number and size of the fans.

This is already an incentivized measure in many locations.

Cost Effectiveness:

Simple payback, new construction (years): 5.3

Simple payback, retrofit (years): 6.3

What's this?

Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.

Comments:

The simple payback for retrofit applications is significantly higher than for new construction because it is much more labor intensive to install.

Detailed Description:

Demand controlled ventilation in commercial kitchens (DCKV) involves controlling the exhaust and make-up air volume of exhaust hoods based on the actual demand.

This equipment varies the speed of the fans based on the amount of heat and smoke present. This is very useful because much of the cooking equipment is typically idle for several hours every day. When equipment is idle or little ventilation is required, the fan motors slow down, reducing energy use significantly. Some of the advanced features of DCKV include:

• Variable air volume (VAV) for exhaust hoods, including applicable controls, that provide only the ventilation required, with a minimum speed of 10% to 50% of maximum.
• Make-up air that can be introduced through back wall supply and/or ceiling-mounted perforated plenums. Make-up air can, instead, be a forced air system that would also have variable frequency drive (VFD) blowers and modulating burners interlocked with the exhaust. During cooking, the speed increases as needed up to 100% until smoke and vapors are removed, keeping the ambient temperature comfortable.
• Adding side panels to hoods to promote capture.
• Replacing vane diffusers with perforated diffusers to promote capture.

Product Information:
Melink, Intelli-Hood TEL, Kitchen Hood VAV Controls Halton Company, MARVEL Gaylord, AirVantage Caddy Corporation, Smart Hood Accurex Engineered Restaurant Systems, Vari-Flow Green Energy Hoods, VAV Hood

Standard Practice:

The current industry practice is manually controlled fans – most are single-speed motors that are left running constantly. It is common in commercial kitchens for cooks to turn on the fans full speed when they come in in the morning, and leave the fans on until the kitchens close at night.

Development Status:

This technology is in the early but well-developed stage of market introduction. According to an EPA Energy Star technology profile, at least 11 DCKV suppliers exist. The Intelli-Hood® is available throughout the U.S. but has not been adopted widely in the Pacific Northwest, although this is improving. Adoption rates should greatly increase in the future due to requirements imposed under California Title 24 Building Energy Efficiency Regulations (effective January 1, 2014).

Chain restaurants are said to be aware of this technology but have not yet developed a business case for implementation (EPA, 2013). Independent restaurants and their dealers may not be aware of the technology.

Non-Energy Benefits:

With specification of a DCKV system, there is no need for a kitchen designer to take chances with a design exhaust airflow that is too low. Oversizing no longer results in excessive energy use. Benefits of noise reduction from the kitchen’s exhaust hood system include a quieter environment for restaurant customers and better communication among kitchen staff, who do not have to compete with noisy fans. Intelli-Hood’s claims include improved fire safety, increased life of ventilation systems, and improved kitchen comfort.

End User Drawbacks:

The main drawback is a higher installed cost. In addition, the controls are a little more complex than the standard installation, requiring some commissioning, user understanding, and maintenance. Equipment installers must be aware of equipment limitations. For instance, some fans have a minimum speed for safe operation; air flow velocities below 500 feet per minute (fpm) can result in deposition of grease in ducts (EPA, 2013). In addition, sensors must be placed in the proper locations to optimize exhaust fan responsiveness.

Installation of a DCKV system requires mechanical and electrical contractors to integrate several different systems, including the exhaust system, VFDs, and the building’s HVAC system (some kitchens have dedicated make-up air systems). Ensuring proper performance across the full range of possible operating conditions and fan speeds is difficult (EPA, 2013).

Operations and Maintenance Costs:

Comments:

The O&M costs of DCKV systems require additional maintenance to ensure continued performance, particularly the proper operation of sensors.

Effective Life:

Comments:

The variable speed feature of DCKV should extend equipment life beyond that expected for standard constant-speed equipment. Expected life is 15 to 20 years.

Competing Technologies:

• Ventilation systems that utilize only temperature sensors
• Fan controls linked to cooking equipment switches
• Custom-designed systems to serve similar functions

Reference and Citations:

SCE, 06/30/2009. Demand Control Ventilation for Commercial Kitchen Hoods
Southern California Edison

FEMP, 02/05/2014. New and Underutilized Technology: Demand Control Ventilation for Commercial Kitchen Hoods
Federal Energy Management Program

Dave Bisbee, 01/11/2008. Customer Advanced Technologies Program Technology Evaluation Report: Demand Ventilation Systems
Sacramento Municipal Utility District

PIER, 09/01/2008. Variable Speed Comes to the (Kitchen) 'Hood
California Energy Commission, Public Interest Energy Research

PG&E, 2007. Demand Ventilation in Commercial Kitchens: Case Study: Mark Hopkins Hotel
Pacific Gas & Electric Company

PIER, 2006. Fact Sheet: Variable Speed Control for Food Service Exhaust Hood Fans
California Energy Commission, Public Interest Energy Research

PG&E, 2009. Clearing the Air in Commercial Kitchens
Pacific Gas & Electric Company, Emerging Technologies Program

Stephen Melink, 12/01/2003. Kitchen Hoods Using Demand Ventilation
ASHRAE Journal

CEE, 03/11/2015. Commercial Kitchen DCV Reports
Consortium for Energy Efficiency

U.S. DOE, 01/16/2013. Demand Control Ventilation (DCV) for Commercial Kitchens, Webinar
U.S. Department of Energy, Better Buildings Alliance (BBA) Food Service Project Team

Derek Schrock, et. al. , 11/01/2012. Demand-Controlled Ventilation for Commercial Kitchens
ASHRAE Journal , 54

EPA, 2013. Technology Profile: Demand Control Kitchen Ventilation (DCKV)
U.S. EPA Energy Star Program

Rank & Scores

Demand-Controlled Ventilation for Commercial Kitchens

2015-1 Commercial HVAC TAG (#11)

Technical Advisory Group: 2015-1 Commercial HVAC TAG (#11)
TAG Ranking: 7 out of 29
Average TAG Rating: 3.5 out of 5
TAG Ranking Date: 03/10/2015
TAG Rating Commentary:

I'm not clear on how this is emerging technology. It's already code in large kitchens and is in many programs already. We have found it not cost effective in small applications.
BPA already has this measure, but there has been very little uptake. There are maintenance issues which can shut down a restaurant, and there are no non-energy benefits to counteract the maintenance issues.
We already have a measure, but could use program help.
I am not aware of case studies demonstrating savings, but believe the concept to be sound, a real market need, and would have some ease of implementation. Persistence of savings and maintenance issues may be present.
My reservation is only that each installation will require a fairly sophisticated contractor to design and install, i.e, there is significant engineering time involved. This may make savings evaluation more challenging - but heck, this is like any other system.
This one seems to be being pushed a lot by vendors. It makes sense, but I'm not sure it can be deemed.
The technology in tests performs but there is little market uptake -- don't know if it is emerging because it is already in our programs
This is required by CA Title 24 code for systems over 5,000cfm -- and ASHRAE. The SPEED program and the CA FoodService Technology Center have lots of case studies.
Code requirements exist for new projects with minimum hp requirement; may be good application for existing buildings.

2009 HVAC TAG (#2)

Technical Advisory Group: 2009 HVAC TAG (#2)
TAG Ranking:
Average TAG Rating:
TAG Ranking Date:
TAG Rating Commentary:

Technical Score Details

TAG Technical Score: 3.7 out of 5

How significant and reliable are the energy savings?
Energy Savings Score: 3.8 Comments:
Jan 2010 Comments: 1. Large potential for energy savings. 2. Large loads and long hours in most restaurants; large gas savings too 3. Good for the particular facility, but the market is limited. 4. Percent savings potential is quite high. How great are the non-energy advantages for adopting this technology?
Non-Energy Benefits Score: 3.7
Comments:
Jan 2010 Comments: 1. Much better. 2. Reduced airflow & noise would likely be perceived as good benefit. 3. Does not seem to provide many non-energy benefits. Energy savings seem to be the key driver in retrofit. For new costruction this seems like the way to go, so I owuld give it a 4 or 5 for new construction and a 2 for retrofit. How ready are product and provider to scale up for widespread use in the Pacific Northwest?
Technology Readiness Score: 4.2
Comments:
Jan 2010 Comments: 1. Manufacturers say they're available. I haven't been involved in such a project yet. Am interested 2. Need alternative manufacturers for competitive pricing. 3. Need to build infrastructure of installing contractors to know when hood modifications are necessary for grease capture issues, as well as locating VSD's and minimum and over ride settings. Single supplier less of an issue as a custom project; retrofits likely to remain as custom projects. This technology should become standard practice for new construction -possible need for market transformation? 4.Not sure how many contractors are capable of installing properly. There are other options (e.g. temp-only systems) that may or may not work as well. Proprietary product can be problem, especially when competitive vendors insist that their product is equivalent or better. 5. Products are ready now. May need more manufactures to compete. How easy is it to change to the proposed technology?
Ease of Adoption Score: 3.3
Comments:
Jan 2010 Comments: 1. Very simple. 2. Simple concept, but difficult to implement. 3. Simple if commissioned correctly. Considering all costs and all benefits, how good a purchase is this technology for the owner?
Value Score: 3.6
Comments:
Jan 2010 Comments: 1. Excellent economics 2. Depends on large or small application. 3. Dependent on building type. 4. New looks like 1 to 3 years, retrofit 6 to 12 years. Varies with connected HP of fans. Would be great with electric heat. So give it an average of 4 years. 5. With such a short payback, it would seem that the private sector should implement this practice with little or no fincancial incentive.

Completed:
4/19/2010 12:16:58 PM
Last Edited:
10/26/2010 4:14:00 PM

Market Potential

Demand-Controlled Ventilation for Commercial Kitchens

Last Edited:

12/27/2012 2:38:33 PM by JackZ

Market Segment:

End users include new and retrofit projects at restaurants, schools, colleges, universities, hospitals, corporate and government cafeterias, full service hotels and some high-end supermarkets.

Regional Fit:

There is much opportunity in this region. One of the big savings effects for this technology is reducing conditioning needed for makeup air. Because of this, the savings for this technology will be more pronounced in areas of more extreme climates and less in milder climates such as along the coast.

Zones:

Heating Zone 1, Heating Zone 2, Heating Zone 3, Cooling Zone 1, Cooling Zone 2, Cooling Zone 3

Performance Trajectory:

This is a new technology in the NW region, but is well-established in California. The technology is not complicated and is quite robust, and there are over 6,000 installations. As with most control technologies, it will continue to evolve and improve, but can be considered to be mature enough now that it will not make enough improvements in the foreseeable future as to render the current version obsolete.

Product Supply and Installation Risk:

Risk of product or component shortage low. See response under “Scalability” for more detail. One potential risk is that the technology is only supplied by one medium-sized company – Melink – increasing the potential for shortages, but we expect any shortages to be short-lived. We do not know of other technologies on the horizon that are likely to overtake this one.

Technical Dominance:

This should ultimately become the industry standard.

Market Channels:

Restaurant and hotel associations/publications, university/college organizations, and HVAC vendors and contractors who handle Melink products.

Regulatory Issues:

No known barriers typically, though older codes in some jurisdictions required maximum airflow at all times. This issue should be researched and addressed if necessary before full implementation in the NW.

Other risks and barriers:

HVAC engineers generally use well established, conservative standards and guidelines for designing kitchen ventilation systems, so some outreach and training through ASHRAE, AEE, and other organizations may be useful.

Basis of Savings:

This technology will likely be able to be defined well enough to become a deemed measure based on horsepower or airflow, hours of operation, and climate zone. We may prefer to make a deemed calculator to calculate estimated savings. The Outdoor Air Load Calculator (OALC) can be used to help calculate energy savings at: www.archenergy.com/oac/.

Evaluation Plan:

Even if we decide to fast-track this technology, a full engineering estimate of savings should be made in the different climate zones and for different sizes of equipment. Fisher-Nickel, Inc. has developed the Outdoor Air Load Calculator (OALC) – a no-cost, publicly available tool that can be used to help calculate energy savings at: www.archenergy.com/oac/. One possibility would be to provisionally deem the technology and monitor savings on some of the installations to verify the savings.

Completed:

12/27/2012 2:38:33 PM by Jack Zeiger