WHEN TO REPLACE RTU
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Roof top units, or RTUs, can last a very long time. Because of this, business owners have a hard time knowing when to replace them versus make them more efficient. According to the Department of Energy inefficient commercial rooftop units "are common and waste from $900 to $3700 per unit annually" [1]. The cost to replace RTUs is very high, causing business owners to stay away from it. But energy savings through the years will at some point make up for the cost. An RTU is ready to be replaced when: The RTU is older than 10 years old, the unit is in poor conditions and have high repair costs, the unit uses R22 refrigerant, and the building requires an improvement in humidity control. If an RTU is not yet ready to be replaced, then retrofitting it with new advanced controls should be considered. RTUs that should be considered for retrofitting have greater than 7 tons of cooling capacity, they are less than 10 years old, and have one speed control. It should also be noted that these units should have another 5 years of life left. If not, then consider replacement [2].
CASE STUDIES
The Department of Energy began the Advanced RTU Campaign to help companies transition to better energy efficient RTUs. The transition allows business owners to save money, energy and make the work places more comfortable. Different companies have decided to join the campaign. Some of the companies have done case studies showing what they have changed and what these changes resulted in. JCPenney decided to retrofit over 1,000 RTUs with advanced controls that allowed them to control the fan speed. Their results showed they saved over 47,000,000 kwh. A 22% reduction from the consumption they had before. This amounted to about $5 million in savings [2].
In 2012 Adidas decided to replace 19 units in 7 locations. In 2013 they replaced 13 RTUs with CEE Tier 2 efficient models. These changes were done at stores in California, Florida, and Oregon. All of the RTUs were condidates for replacement becuase they were 14 years old. Adidas also noticed that they were using R-22 refrigerant, also making them good candidates for replacement. After all the changes made, they estimated a 20-40% electricity consumption lower than standard efficiency RTUs. Their repair costs were also lowered [3].
In 2010, Walgreens pushed for a change as well. Their plan was to retire older RTUs with newer and more efficient RTUS. They also decided to review size their buildings and make sure their RTUs were not too big for their building. They found that, out of 150 stores, many of them could downsize and save in energy consumption. They had an average of 5 ton reduction per RTU, which lead to $800,000 saving from material not used and $325,000 from labor. Replacing RTUs can be extremely beneficial. As seen by many different companies who have already commited to this change. Estimating the exact amount of energy and monetary savings can be found once the company sees what their current units are. Companies will need to find the average size of their RTUs and if they are a bigger size than what they need. They will also need to figure out the units efficiency ratings. The new units will need to have IEERs of 14 or higher [4].
In 2012 Adidas decided to replace 19 units in 7 locations. In 2013 they replaced 13 RTUs with CEE Tier 2 efficient models. These changes were done at stores in California, Florida, and Oregon. All of the RTUs were condidates for replacement becuase they were 14 years old. Adidas also noticed that they were using R-22 refrigerant, also making them good candidates for replacement. After all the changes made, they estimated a 20-40% electricity consumption lower than standard efficiency RTUs. Their repair costs were also lowered [3].
In 2010, Walgreens pushed for a change as well. Their plan was to retire older RTUs with newer and more efficient RTUS. They also decided to review size their buildings and make sure their RTUs were not too big for their building. They found that, out of 150 stores, many of them could downsize and save in energy consumption. They had an average of 5 ton reduction per RTU, which lead to $800,000 saving from material not used and $325,000 from labor. Replacing RTUs can be extremely beneficial. As seen by many different companies who have already commited to this change. Estimating the exact amount of energy and monetary savings can be found once the company sees what their current units are. Companies will need to find the average size of their RTUs and if they are a bigger size than what they need. They will also need to figure out the units efficiency ratings. The new units will need to have IEERs of 14 or higher [4].
Sources
[1] "Replace.Repeat.Reap Rewards," [online], November 28th 2016, Advanced RTU Campaign, website:http://www.advancedrtu.org/
[2] "How do I know if my RTUs are effiecient? When do I replace or Retrofit Them," [online], November 28th 2016, Department of Energy, website:http://energy.gov/eere/buildings/articles/how-do-i-know-if-my-rtus-are-efficient-when-do-i-replace-or-retrofit-them.
[3] "HVAC Rooftop Units (RTU's)-Certified Air Flow Testing," [online], November 28th 2016, Laminair, website:http://laminair-tab.com/commercial-test-and-balance-chicago/roof-top-units-rtus/.
[4] "adidas RTU Replacement Program," [online], November 28th 2016, Department of Energy, website: http://www.nrel.gov/docs/fy14osti/61286.pdf.
[5] "Case Study: Walgreens RTU Replacement Program," November 28th 2016, Department of Energy, website:http://betterbuildingssolutioncenter.energy.gov/sites/default/files/attachments/Walgreens-ARC-Case-Study.pdf.
[1] "Replace.Repeat.Reap Rewards," [online], November 28th 2016, Advanced RTU Campaign, website:http://www.advancedrtu.org/
[2] "How do I know if my RTUs are effiecient? When do I replace or Retrofit Them," [online], November 28th 2016, Department of Energy, website:http://energy.gov/eere/buildings/articles/how-do-i-know-if-my-rtus-are-efficient-when-do-i-replace-or-retrofit-them.
[3] "HVAC Rooftop Units (RTU's)-Certified Air Flow Testing," [online], November 28th 2016, Laminair, website:http://laminair-tab.com/commercial-test-and-balance-chicago/roof-top-units-rtus/.
[4] "adidas RTU Replacement Program," [online], November 28th 2016, Department of Energy, website: http://www.nrel.gov/docs/fy14osti/61286.pdf.
[5] "Case Study: Walgreens RTU Replacement Program," November 28th 2016, Department of Energy, website:http://betterbuildingssolutioncenter.energy.gov/sites/default/files/attachments/Walgreens-ARC-Case-Study.pdf.