Wednesday, March 05, 2008

Brilliant! Why Air Conditioners Run All Winter Long

The decision to operate both heating and cooling sources at the same time is a waste of energy and money in several ways. I'll tell you my story below. But first, consider this:

1.) The air conditioner's compressor and other critical components were not designed to achieve heat exchange in cold temperatures. Sure, it will "run," but doing so will hasten its mechanical demise and accelerate its need for replacement. Ice formation on the evaporator coil is a clue that something is amiss.

2.) Is the space too warm? That means the heating system is running too long at too high a setting. If you have control of the heating system thermostat, why not lower the setting? If you have no thermostatic control, open windows to various degrees to vent the excess heat.

3.) On an apples-to-apples basis, a unit of electricity is more expensive than a unit of fossil fuel (natural gas or heating oil). Running an air conditioner during winter is an expensive cure for excessive heat consumption. It's like hitting yourself on the head with a hammer to cure a headache.

4.) Electricity for air conditioning must be generated; generating assets must be capitalized by the provider-- and the provider will simply recoup its investment by charging customers that much more.

5.) Energy use is not without consequence. Heating and cooling systems both rely ultimately on fuel combustion. Combustion emissions collect in the atmosphere to the detriment of our climate and health. It's a good idea to use the energy you need, but no more. Running heating and cooling systems at the same time is a choice of dubious merit.

Bear with my little story here. A checklist will appear at the end, extremely relevant to industrial decision-makers from Maine to Missouri, and a few other places, too.

I own one 847 square-foot residential rental property. Understand that this is a fifty year-old condominium. The building contains six apartments, all of which are served on one master meter for natural gas and electricity. That’s the way they were built back in the 1950s. As a consequence of this design, all utility costs are included in the rent. Regardless of how much an occupant runs air-conditioners, lights, televisions, video games, or any other appliances, he enjoys the same, predictable out-of-pocket costs each month.

These apartment units have been rehabbed over the years, but some more so than others. Being the energy geek that I am, I have updated mine with Energy Star appliances and energy-efficient, double-pane insulated windows. Unfortunately, most of the neighboring units do not have similar upgrades. Old, leaky single-pane windows are predominant throughout the building. There is nothing to compel unit owners to make any improvements over and above the usual safety and sanitation requirements imposed by the building code and related regulations.

Space heat is provided by a hydronic (hot water) system of radiators. The management turns on the boiler on October 1, and it stays on through April. The apartments lack individual thermostats for controlling the ambient temperature during heating season. The radiators do have knobs for restricting hot water intake, but these are not really effective. The boiler is cranked up to suit the needs of the coldest residents—that is, those with the old, leaky windows. The rationale here is that too much heat is preferable to too little. If there are any unseasonably warm days during this time (and there always are), people who are too warm usually open the windows to attenuate the heat.

Everyone, that is, except for the young man who rents from me.

I popped in to handle a routine repair on a chilly Saturday in February. The tenant was out, so the unit was unoccupied. I found not only a number of lights on, but also a 2.5 amp oscillating pedestal fan. And if this was not enough-- the air conditioner was running. In FEBRUARY. This was apparently to counteract the excess heat trapped in the unit by the very efficient windows that I had installed just last year.

I’m sharing this with you because the underlying facts of my story help to explain energy waste in an industrial setting. Think about it:

Commitment to vintage technology. It’s not unusual for a 1950’s vintage multifamily property to have centralized meters. That’s a design choice that would have repercussions for decades to come. Similarly, there’s a lot of industrial activity taking place in facilities that are 30 years old or more. When it comes to technology, many manufactures continue to “dance with who brung ‘em,” and the cost of doing so is becoming increasingly dear.

Lack of accountability and awareness. The “all utilities included” format made a lot of sense for years—as long as energy was cheap. But if you never see the bill for the service you consume, why bother to use that service wisely? Apartment or factory, the outcome is the same.

Overhead instead of direct cost accounting. Okay, so the utility costs for a master-metered multifamily building are pooled and divided evenly among the participating units in the monthly condo fee. One person may be careful about energy use, but ends up paying for the waste of others. In industry, accountants will take the energy bill for the whole plant and divide it across departments according to the number of labor hours booked that month, or by the number of square feet. Result: no incentive to save because there’s no way to trace the benefit.

"That’s the way we've always done it." People in multifamily housing have been using windows in place of thermostats for years. It’s an institutionalized habit. The same is true for a lot of industrial energy housekeeping.

Bad return on investment (ROI). How can you guarantee a bad ROI for an energy improvement? Do random, isolated projects instead of system-wide optimization. I needed new windows anyway, but opted to make them as efficient as possible. But note the unintended interaction—a tenant running the air conditioner during the winter to offset the space heating! At least I can take some measure of comfort in knowing that the cost of this waste is being pooled with my neighbors. Think now (true story) about the fabrication facility that refuses to fix compressed air leaks, so it runs 50 percent more compressor capacity than it needs to make up for the volume lost due to leaks!

Industrial energy waste exists for a reason. Disjointed fiscal authority and accountability under one roof is deadly. Think about my condo building. Do the departments in your facility work the same way?



Post a Comment

<< Home

Who links to my website?