Friday, April 9, 2010

Water Use in Restaurants and Supermarkets

Water is often taken for granted, but the cost of water is approaching a penny a gallon in some jurisdictions in the US, including fees for both water and sewer. Since a restaurant may use 3,000 gallons on a slow day and 7,000 gallons on a busy day, the dollars add up quickly over a year.  Grocery stores with fish departments, meat departments, deli, bakery, and produce may use even more water.

Both restaurants and large supermarkets have water softeners and filters for ice machines, beverage dispensers, and hot water, to be sure the water they use is pure and clear. Wasted water costs money in filters and softening in addition to the utility costs.  To save water, tactics include:

  • low flow toilets and urinals
  • low flow lavatories (0.5 gpm)
  • low flow hose faucets on pre-rinse sinks (2.0 gpm instead of 4.5 gpm)
  • reducing flow through ice machines 
  • reducing flow through dipperwells
  • ensuring that dish machine valves are leak-free
  • repairing leaks in faucets
  • adding pressure regulating valves to water services where pressure is too high

However, hundreds of gallons are used every night in after-hours cleaning, and none of the tactics above address this.  I recently measured flow using a transit time meter for 24 hours at a restaurant on a very high volume Saturday.  Transit time meters clamp on the outside of a water pipe and use ultrasonic waves to measure flow without interrupting service.   Data is collected every 10 or 20 seconds, and you can download it to a computer to graph usage over the course of a day.  Here is what my graph looked like using Excel:

A 1997 study asserted that 1% of water use in restaurants is used for cleaning.  From the graph above, however, we can see that over 600 gallons was used by the after-hours cleaning crew.  In my teens, I was a cook at a pizza and grille restaurant, and once we closed for the night, I had to help clean the kitchen. We used buckets, scrubbers, mops, and hoses to clean the entire kitchen at least twice and often 3 times.  I know from experience as well as from the actual data, cleaning a kitchen uses a lot of water.

If you run a restaurant or grocery store, consider finding your water meter and taking a reading at the end of the night before cleaning, and again before prep starts in the morning.  Subtract the two to get an estimate of gallons used for cleaning.   To manage this use on a regular basis, add a remote reader to the water meter and tie it to a web-enabled data logger to generate regular reports on your PC.   If you need any help with this, please let me know using the form at right, and we'll lend a hand.

Monday, March 15, 2010

Google PowerMeter - Real Time Power Metering

I installed a Google powermeter for my house this weekend, a TED 5000.  This measures power being used, and converts it to carbon footprint and to dollars.   Virginia rates are NOT deregulated, so they are low compared to Maryland or DC, but I went ahead and typed in my rates from my local power company, NOVEC.   Here is my current usage:

But what is even cooler than the dashboard (which can display power, carbon footprint or $) is that you can see what how power varied over a day or week or month.  Here is a sample graph showing our use over a day.

Seeing a 4.5 jump in kW from an electric water heater that turns on doing dishes is almost startling. Also, seeing 500 watts burning in the middle of the night leads to an inventory of ignored appliances like TV, computer, printer, and Xbox.   As I start to check the graphs, I inevitably start to think of ways to cut energy use.  Once installed, this is a great tool for saving energy.

Installation is not difficult, but you need to be an electrician or an engineer (or foolhardy) to do it yourself since there is danger of electrocution.  An electrician could install it in 2 hours in most cases.  The manual that comes with the meter is pretty clear, but here are photos of the basic install.  Needless to say, please read the manual - this is just a cursory overview.

Now that you have a power meter installed, you can measure the effectiveness of all future energy saving steps, plus you will probably save energy by the simple act of measuring it.  

COMMERCIAL BUILDINGS - While this meter was for a residence, you can create a similar setup for an office, store or commercial building, where the dollars are much higher. There are three phase versions of these meters for larger electrical services, and you can still get remote web access for ease of use. One popular vendor is E-mon D-mon, but there are several others as well. One important feature you can add is the ability to monitor gas and water meters as well, so you can check on all utilities via the web. In addition to saving energy and water, this lets you check on your landlord or tenant, who otherwise might make inadvertent errors.

 If you need help on any of these issues (or would like a link to see my power meter in action), please let me know via email

Thursday, February 25, 2010

Green Business Challenge Feb Meeting

We had another meeting today on Loudoun County's Green Business Challenge this morning.   Loudoun County's Chamber is working hard to get recognition for green businesses, so if you're a neighbor in the County, let me know and we'll help you out.   There is no charge for this challenge or our help, the whole idea is to come together to save energy, and oh by the way, save money.

Here's the pdf to get started.  If you are curious, the Chamber is planning a kickoff breakfast for any interested business to explain how this works.  We hope to follow that up with hands-on workshops, to help each other get our businesses through the challenge.  Pencil in April 16th for the first event (well, probably April 16) and send me an email (mdwyer at dwyer dot com) if you want to be attend.   

We are also starting an online community for this challenge to help solve problems as they come up.  I hope we can share success stories as well as solve issues as this goes along.  If you have any opinions on this, I'd love to hear them. 

Technorati: PN5CQ99Y6THG

Saturday, February 20, 2010

Google Energy Gets the Green Light

The Federal Energy Regulatory Commission has approved Google's application to be an energy supplier. This could be a powerful, long term boost for the green power movement, where a combination of false prophets and doubtful consumers slow the adoption of renewable sources.

At first glance, this ruling simply appears to give Google the right to buy and sell energy. Yes, that is what Enron did, but Google and Enron have very different approaches to business. Enron was about corruption, insane risks, and hiding the truth. Google  certainly does not hide the truth. Google revels in the truth - rolls around in it like it's chocolate. Arguably, that is what their PowerMeter is all about - showing you the truth about your energy use. With their free software and a $200 meter, you can see your energy use, live, 24/7.

Google's efforts as a supplier may also disrupt unscrupulous practices in energy procurement. Some procurement companies cloak their bid process in mystery and create strangling contracts that refuse to let you review energy use with any other consultants.  Procurement companies may be embarassed if another company found savings they missed.  While these companies do point out discrepancies in billings, they often approach it as an accounting issue, not an engineering issue.   Seeing energy discrepancies is one thing - to figure out what happened, you need boots on the ground.

So, having a truth company like Google enter the energy supply business should be great, even if the power they sell is initially from a traditional energy source. In the long term, the greater question is how will they tie this to their renewable energy initiative?   Will their increasing involvement in clean power help them push new technology, like the BloomBox fuel cell?

Monday, January 25, 2010

Notes from ASHRAE 2010

Saw several excellent sessions this weekend at ASHRAE 2010, including a short course on Energy Management, and seminars on ventilation and H1N1, advances in case refrigeration efficiency, ice machine design, HVAC design of labs in humid climates, and chiller/tower maintenance tips. A short video below are my first impressions of a couple of these sessions.

Conference is at the Rosen Shingle Creek conference center. It is a beautiful site, and feels very luxurious, which makes me picky I think.
1) video screens are too low (blocked view) and too small (no super bowl parties)
2) no LAN outlets in lobbies
3) practically no visible electrical outlets in lobbies for laptops

People at conference have been great, and sessions informative.

Wednesday, December 16, 2009

Lighting Energy & Tax $ Calculator

Lighting DollarsHigh efficiency, low glare lighting is a good investment in a commercial building, and saves tax dollars as well.  You can check savings yourself with our embedded google doc spreadsheet below.

Fixtures like Leda's Pure FX, create a pleasant office environment at remarkably low energy levels (well under 1 watt per sqft).   LED lighting is nearly here as well, but most real world manufacturers (e.g, Acuity) still show lumens per watt in the 40+ range, and not the incredible 180+ that Cree achieved recently in their test lab.

While we all want to be green, in this economy, we all want to know How Much? too.  Checking with our local rep at Ambiance Lighting, the PureFX runs about $200 each, but you probably use fewer fixtures.   Also, there are significant savings on your utility bill and tax bill which can justify the expense.  If you are looking for a new building standard, or renovating for new tenants, you should certainly take advantage of the current tax deductions which expire in a few years.

Friday, December 4, 2009

Mechanical Equipment Sizing

We remember miserably cold February nights and sweltering hot August days for years, but the reality is that they are rare.  Of course, we want to be comfortable in offices, homes, and stores, so we want plenty of A/C and heating.  But it is important to size heating and cooling systems so they keep us comfortable most of the time, not all the time.

If we size systems so that we are always comfortable, the system is expensive to build, expensive to operate and will perform poorly on normal days.   Looking at weather data for Northern Virginia, for example, we can see that it is hardly ever hotter than 92F and hardly ever colder than 12F.  The chart below shows hours per year at different temperatures for typical business weekdays and for nights and weekends.   This data is for a typical year, as defined by the US NOAA weather service, and obtained from NREL.

Other cities are different, but the patterns are similar.  Boston hardly ever gets hotter than 87F.  And Miami hardly ever gets colder than 50F.

Oversized units cost more in construction, and the costs cascade through the building.   A commercial roof top unit that is 20% larger than necessary weighs more, takes up more space, requires larger ducts, larger wire, larger electric service and costs far more to buy and install.   In use, it burns power and fuel, driving up your electric bill.   In exchange for that extra expense, you may be comfortable on the hottest days, but otherwise the A/C removes less humidity than a properly sized unit, making it feel clammy indoors.

If you manage a number of buildings, pick an old one, or pick a space that is underperforming financially, and experiment.   Modernize, disconnect or replace equipment.  Monitor systems, weather and bills, and document the results.  If you have tenants, get their help and publicize efforts, so everyone can pitch in, and everyone gets credit for the changes.  Once you modify one site, the rest will be easy, but you need to engineer it carefully to avoid problems.

Friday, November 20, 2009

Stairwell Lighting - Turn it off?

In the middle of the night, in an unoccupied building, do we have to leave the stairwell lights on?  No, but we can't just turn them off completely.  The new life safety code requires a bi-level fixture with a fail-safe occupany sensor. This should pay for itself in about 5 years compared to the usual 24/7 fixture.

Not every city or state uses the same code, of course, but the 2009 Life Safety Code from NFPA says you can turn lights down with a motion sensor but not completely off - and the motion sensor has to be fail safe.

Specifically, NFPA 101 section says:   Automatic, motion sensor type lighting switches shall be permitted within the means of egress, provided that the switch controllers are equipped for fail-safe operation, the illumination timers are set for a minimum of 15 minute duration, and the motion sensor is activated by any occupant movement in the area served by the lighting units.

In addition, section says: The floors and other walking surfaces within an exit and within the portions of the exit access and exit discharge shall be illuminated as follows:

During conditions of stair use, the minimum illumination for new stairs shall be at least 10 ft-candles (FC), measured at the walking surfaces. The minimum illumination for floors and walking surfaces, other than new stairs during conditions of stair use, shall be to values of at least 1 ftcandle (FC), measured at the floor.

Translation: you need a special bi-level lighting fixture with built-in fail-safe motion sensor. Vendors are just beginning to make these, so there is a premium price, but a California case study showed savings of 440 kWh per fixture. At a typical 15 cents a kWh, that works out to $66 per year. Our Columbia and Lamar Lighting rep (One Source) says a budget price is about $200 to $250 each, so if $300 installed, then a 5 year payback seems reasonable. Be sure to compare expected savings before making a purchase, as minimum energy use may vary by manufacturer.

Bonus: You can earn rebates from most utilities plus federal energy tax deductions for lighting improvements.

Caveat:  This discussion is all based on NFPA codes, and NFPA does not publish the ubiquitous 2009 International Codes. The International Building Code (IBC) only requires 1 FC at all times. Per Section 1006.2: Illumination level. The means of egress illumination level shall not be less than 1 foot-candle (11 lux) at the walking surface. 

So, if you are strictly governed by IBC, you might get away with 1 FC at all times, unless you wanted higher levels to provide a sense of security.  Keep in mind that this would not comply with the 2009 NFPA Life Safety Code.  So, even if a building inspector allowed it, a fire inspector might not.   Be sure to chat with your local fire marshall before making any decisions (or ask your engineer to help).

Thursday, November 19, 2009

LoCo Green Business Challenge

Loudoun County kicked off a Green Business Challenge today, so we signed up and went down to the County Boardroom down the street to see how to participate.  County Supervisor Andrea McGimsey and Loudoun County Energy Manager, Najib Salehi, were leading this effort with Tony Howard of the Loudoun Chamber of Commerce, and several County and local business people.  

My only question was how do we help each other?  Not just the 50 people there today, but in ALL our counties/countries.  I think one of the answers is social media, or a blog, or a website, but there was little movement today to arrange that.  Perhaps the Chamber can do that, so perhaps I should join and share some energy.  And meanwhile, I need to set up a meeting with our landlord and see if we can all save some energy, and do a better job at recycling.  Nothing we have not practiced before, but fun to get some points for it.