REPOST: How Effective is Your Air Conditioning Unit?

Consumer Reports tested several brands of window air conditioning units to determine their cooling ability. Read the verdict on this article from WFMYNews2.com.

 

Image Source: wfmynews2.com

Portable air conditioners sound like an easy solution for cooling a room that can't accommodate a window air conditioner, but many are returned by unhappy customers.

So Consumer Reports tested to see if there are some good choices.

With temperatures rising outside a seemingly easy fix is a portable air conditioner. It draws in warm air and exhausts it outside through a hose that connects to your window.

Consumer Reports tested eight from brands including Honeywell, Haier and Frigidaire. Prices range from 250 to more than 500 dollars.

Consumer Reports used a special chamber to test their cooling power. The temperature outside is kept at 90 degrees, the humidity at 70 percent. Inside, each air conditioner is set to 75 degrees.
 
Strings of thermocouples record temperatures throughout the room. The results were disappointing.

"None of these units, not even the biggest ones, could get our test chamber below 80 degrees even after an hour and forty minutes," said Bob Markovich, of Consumer Reports.

That was true even of the most expensive unit tested, including a $550 Honeywell which promises it "cools up to 550 square feet." It struggled to cool the test chamber, which is half that size.

"Window air conditioners are much more effective and they tend to cost less," said Markovich.
Consumer Reports found several window air conditioners to recommend. Top-rated for larger rooms, a $350 LG. For medium-sized rooms an LG for $240. And for smaller rooms a $210 GE is a Consumer Reports Best Buy.

Consumer Reports says be sure to pick the right size air conditioner for your space. If the unit is too small, your room won't get cool enough. But an air conditioner that's too big may make it feel cold and clammy.

Hobson Air is a family owned and operated business in Texas that has been servicing HVAC systems since 1962. Visit this blog for more discussions on HVAC improvements.

REPOST: Ventilation rates and sick building syndrome symptoms

The Lawrence Berkeley National Laboratory discusses the link between poor ventilation andsick building syndrome, which is a series of symptoms associated with poor air quality that can negatively affect the quality of life in a home or workplace.

Image source: iaqscience.lbl.org

Many studies have investigated the linkage between ventilation rates and the proportion of the occupants reporting sick building syndrome (SBS) symptoms. Most studies have collected symptom and ventilation rate data from sets of five to 160 buildings or building spaces and assessed how symptom reporting rates were correlated with ventilation rates, using statistical models to control for other factors. A few studies experimentally manipulated ventilation rates in one or a few buildings and assessed how symptom reporting rates or symptom severity varied with changes in ventilation rate. Occupants were unaware of the ventilation rates during the various experimental periods. Considering the full set of studies, ventilation rates spanned a very broad range from zero mechanical ventilation and an uncharacterized amount of infiltration to total ventilation of more than 100 cfm per person. In many individual studies, building ventilation rates spanned a smaller range from approximately 10 to 35 cfm per person.

Three critical reviews of this literature have been performed. In the review by Seppänen et al. [24], 20 out of 27 studies found a statistically significant increase in reporting of at least one SBS symptom among occupants of the study buildings with lower ventilation rates. In nine of these studies, there was at least an 80% increase in the fraction of occupants reporting at least one of the types of SBS symptoms in the buildings with lower ventilation rates. The second critical review [32] was performed by an interdisciplinary group from Europe and concluded that "increasing the ventilation rate .....decreases the prevalence rates of SBS symptoms." This interdisciplinary group also concluded that "ventilation rates below 25 liters per second per person [53 cfm per person] in offices can increase the risk of health and comfort problems". The third critical review [33] by another interdisciplinary group concluded that "higher ventilation rates in offices, up to about 25 L/s [53 cfm] per person are associated with reduced prevalence of sick building syndrome symptoms".

The largest U.S. study of building characteristics and occupant symptoms is the EPA Building Assessment Survey and Evaluation (BASE) Study of 100 representative office buildings. Analyses of data from this study [34] indicate a general decrease in SBS symptoms as study space ventilation rates increase from as low as 10 cfm per person up to approximately 25 to 35 cfm per person, while current U.S. building codes and professional standards generally require a minimum of 15 to 20 cfm per person in offices. Twenty percent to 30% fewer occupants reported SBS symptoms in study spaces with ventilation rates above 20 to 25 cfm per person, compared to study spaces with lower rates typically ranging between 10 and 20 cfm per person.

In work performed for this IAQ Scientific Findings Resource Bank, the published data relating ventilation rates in office buildings with prevalence rates of SBS symptoms were analyzed statistically [35]. This analysis yielded a quantitative estimate of how, on average, the prevalence of SBS symptoms varies with ventilation rate per person. The key results are provided as Figure 4 which shows the estimated curve of relative SBS symptom prevalence (RP) plotted versus ventilation rate with RP equal to unity at a ventilation rate of 17 cfm per person, which is the minimum required ventilation rate for offices (based on an assumed default occupant density of 5 occupants per 1000 ft2) in the applicable ventilation standard of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers [36]. The central estimate of RP is indicated by the bold red line and the 95% confidence band is indicated by the shading. The RP increases from 1.0 to approximately 1.15 (95% confidence interval: 1.09 - 1.22) as the ventilation rate drops from 17 to 10 cfm per person. RP decreases from 1.0 to approximately 0.67 (95% confidence interval: 0.55 - 0.81) as ventilation rate increases from 17 to 50 cfm per person. At higher ventilation rates, the statistical uncertainty in RP becomes large relative to the estimated deviation from unity.

Figure 4: Estimated relative SBS symptom prevalence in office workers versus ventilation rate. Image source: iaqscience.lbl.gov

Interpretation of Figure 4 may be facilitated by the following application example. Consider a situation in which the SBS symptom prevalence is 20% when the ventilation rate is 17 cfm per person. Based on the RP curve in Figure 4, one would predict an SBS symptom prevalence of 23% (20% times 1.15) with 10 cfm per person of ventilation and a symptom prevalence of 13% (20% times 0.67) with 50 cfm per person of ventilation. The findings also indicate that, on average, increases in ventilation rates above 50 cfm per person will not substantially reduce SBS symptom prevalence although the uncertainty of the estimates are high in this ventilation-rate range.

The analyses underlying Figure 4 have several important limitations. The amount of original data available in a useable form was quite limited. Only eight useable studies with 43 data points were identified. Because of the limited data, distinct analyses for different types of SBS symptoms were not performed. In actuality, the relationship of ventilation rates with SBS symptoms may vary with symptom type. In addition, one would expect the relationship of SBS symptom prevalence with ventilation rate to vary depending on the strength of indoor pollutant sources, the levels of outdoor air pollution, and other factors. For example, in buildings with high indoor pollutant source strengths ventilation rates may have a larger impact on SBS symptom prevalence rates than in buildings with weak indoor pollutant sources. Thus, Figure 4 provides only an estimate of the average relationship, based on the available data. The equation shown on Figure 4 should not be used for ventilation rates below 10 cfm per person or above 70 cfm per person.

With respect to the impact of ventilation rates in schools on SBS symptoms in students, only two studies were identified. The study resulting in Figure 3, relating ventilation rates in two elementary classrooms with school work performance, included surveys of SBS symptoms in students. No statistically significant relationship of ventilation rate with SBS symptoms was identified [37]. The second study intentionally changed ventilation rates in four university computer classrooms [38]. When carbon dioxide concentrations were higher, corresponding to less ventilation per student, there were statistically significant increases in four of nine SBS symptoms (throat, breathing, headache, and tiredness symptoms increased). However, there were statistically significant increases in only two of these symptoms (headache and tiredness) with decreased air exchange rates (rates of outdoor air supply per unit indoor air volume).

Many of the studies of how ventilation rate in affects SBS symptoms have measured indoor CO2 concentrations. In the majority of these studies, a larger fraction of occupants reported SBS symptoms in buildings with higher CO2 concentrations.

Hobson Air provides a myriad of HVAC services, including indoor air quality testing and analysis. Visit website for more on HVAC systems and indoor air quality.

REPOST: Energy expert reveals simple, low/no-cost energy habits to save millions

Stephen Baack of the U.S. Army website writes about how one expert’s simple suggestions could complement the efforts of the military to cut back on energy consumption.

Lights on in an unused maintenance bay were one of many issues that Lyman Parkhurst,
a Sain Engineering Associates inspector who regularly visits Army installations as
part of Installation Management Command's annual Energy and Awareness Conservation
Assessments, found during his trip to U.S. Army Garrison-Ansbach, Germany, in late January.
During his outbrief, Parkhurst revealed a list of simple, low/no-cost energy habit changes
                         community members can make that could be saving millions of dollars.                        Image Source: www.army.mil

ANSBACH, Germany (March 13, 2014) -- It's the type of problem that goes unnoticed every day: an air conditioning unit blasting cool air only feet away from a propped-open door, a bedroom window left open next to a maxed-out heater, and powerful halide lights illuminating an unused maintenance bay for the entire day. 

Despite the millions of dollars of energy-saving enhancements rolled into the billions of dollars of Military Construction Program work the Army has completed in the last five to six years across its inventory, old habits have undermined these technological leaps. 

"Hundreds of billions of dollars were spent and our energy performance has not improved," said Lyman Parkhurst, a Sain Engineering Associates inspector who regularly visits Army installations as part of Installation Management Command's annual Energy and Awareness Conservation Assessments. "We may be better heated in the winter and cooled in the summer, and have better lighting, but we're using it all more than we need or the designers intended for it to be consumed." 

On Parkhurst's list of garrison walkthroughs in January and February was U.S. Army Garrison Ansbach. As at other installations, Parkhurst found things USAG Ansbach is doing well and things it could be doing better. While some of the issues he brought up during his briefing here only apply to the Directorate of Public Works such as long-term lighting upgrades and control setting changes, a significant portion of the problems he addressed are correctable through changes community members can make. 

Fortunately for the Soldiers, family members and civilians who live and work here, Parkhurst stressed that many solutions are low or no cost. Moreover, "the biggest low/no cost items are the simplest issues," he said. 

Regulating the heat properly in a facility, keeping windows closed and turning off lights were all major no-cost solutions he discussed at his briefing. These issues apply not only at houses and offices, but also at military spaces like hangars and maintenance bays. 

"The hangar doors left open only a few inches is the same as leaving a couple of personnel doors open," Parkhurst said. "The barracks and shops have a number of doors propped open with a rock or trash can or sign." 

All of those open doors, he added, add thousands of dollars in heating costs to each building -- not to mention that rocks or other objects used to prop open doors often cause damage. That might mean having to replace the entire door at a cost of several thousand more dollars.
"It's more than conserving energy; it's causing damage that we simply don't have the money to repair," he said.

BEHAVIOR CONTROL 

"We put computer control systems in place to control the heat and ventilation, and in some cases the lights," Parkhurst said. "So, we can monitor and control maybe 30 to 50 percent of the total energy use, but over the years that has meant an investment at most garrisons of $4 million to $5 million just to install and takes a handful of people to operate. We could always add more automatic controls to the lights and radiators and faucets, but is it necessary to add automatic faucets at $400 instead of changing our behavior to simply turn off the water and not waste it?" 

Parkhurst offered plenty of good practices, but said it boils down to behavior control.
"Behavior has such a huge impact, and the cost can be zero," he said. 

To illustrate his point, Parkhurst brought up a story a local national told him during a trip to another garrison. The local national had rented out a duplex for years to an assortment of tenants. About half of the time an older German couple rented the space. The other half, a succession of military renters occupied it, from couples to small families. The difference in energy consumption was eye-opening. 

"Through years of utility data and tenants he said the Americans used three to five times the amount of heat and five to 10 times as much water," Parkhurst recalled. "Identical units and equipment -- just different people." 

When it comes to energy conservation, it turns out USAG Ansbach is doing many things well.
In general, Parkhurst said USAG Ansbach's temperature regulation is the best area.
Improvements since the last assessment include the installation of radiant heating panels in hangars 1, 4 and 5 at Katterbach Airfield, and at the hangars and maintenance shops at Storck Barracks. New LED streetlights at Katterbach and Bleidorn are also a big plus, in addition to improvements to control systems and the installation of photovoltaic panels at Storck. 

"But, putting in new equipment is costly, and the results could honestly be better," Parkhurst said. "Because radiant heating is quiet, some of the bay doors were left open and people were not aware the heat was on and going out the doors. The better insulation in the housing helps keep the houses warmer, but now many are over-heated and not meeting the energy-savings targets; i.e. delivering the cost savings to justify the added expense in constructing them better."

TIPS 

Parkhurst provided a list of items the USAG Ansbach community can improve on with little or no cost. 

Setting thermostatic radiator valves appropriately was one of those big, no-cost, simple solutions. For example, generally in the winter users should set the valve at 3 in offices, 2 in hallways and 1 on the entry radiator, he said. A 5 will often overheat a space and, "when it's combined with an open window, then we are sending dollars flying out that window." 

Also, keeping windows closed is important to remember, he said, except for the short periods of time each day users vent their homes. Venting should be one or two hours a day, not 24/7.
"That and shutting off lights that are not needed," he added, "either because there's plenty of natural light or it's during lunch break or the area is unoccupied." 

Hangars and maintenance bays also have a big role to play. 

"With the large metal halide lights that take 10 to 15 minutes to warm up, people tend to enter the bays in the morning and turn all the lights on and leave them on until everyone leaves for the day. But, some buildings had half or more of the bays unoccupied and also most had good natural lighting from plenty of windows. If the bay is unoccupied but it's dark outside, then only turn on a portion of the lights. 

"If there are going to be more aircraft or vehicles moved into the bay," Parkhurst added, "turn on the additional lights, go connect the tug to the aircraft and move it into the bay. By the time you need the light it will be on. Even better, label the light switches as to which portions of the bay they light: east, west, Bay 1, Bay 2, etc."

CHANGING COSTLY HABITS 

"The assessment was an excellent look in the mirror for us a garrison," said Kevin Griess, deputy garrison commander, who was at the Jan. 31 briefing. "It is always beneficial to have a highly qualified and experienced third-party subject-matter expert such as this to conduct a thorough review of our garrison. The assessment provided valuable insight to some positive improvements that we can make as a garrison and a community." 

The numbers Parkhurst shared with USAG Ansbach leaders during his briefing told a story of increasing prices and unchanging habits -- something Griess wants to turn around.
Since 2007, USAG Ansbach's facility energy consumption has remained relatively stable at roughly 325,000 MBTUs per year (for reference, one MBTU in this context equals one million British thermal units, and one BTU is equal to the amount of heat energy required to increase the temperature of one pound of water by 1 degree Fahrenheit). In fiscal 2007, that cost the garrison almost $10,000,000. In fiscal 2013, that price went up to nearly $16,000,000. 

"It all comes down to consumption," said Griess, who stressed that changing consumption patterns gives an "immediate and measurable" reduction in costs -- and is easy to do. 

"I say easy because it is easy to close a door, to close a window, turn off the lights, etc.," Griess said. "It is not so easy to change our habits, and that is what we must do as a community. 

Reducing energy consumption brings direct dollars right back to the garrison; dollars that can be used for other projects that benefit Soldiers and their Families." 

Unfortunately for the goal of better energy consumption, too many people have yet to come around to Griess' and Parkhurst's attitude of conservation through behavior control. 

"We really do tend to think, well there's so much money and waste in DoD or the Army that this won't make a difference, that putting this rock in the door is no big deal, that leaving this hangar full of lights on all night is not that important," Parkhurst said. 

"The reality is that the energy bills have to be paid," Parkhurst continued, "and maybe that means we cut a few staff positions, which means the door is not repaired, along with that broken window, and then there's water damage inside, and that causes mold, which means mold remediation, which is costly, and now we have to make some other cuts or forego some repairs. We know what that does to helicopters, or vehicles, or your own car or house."

Hobson Air provides customers with expert vent and duct cleaning services. Visit this website for more on the importance of clean HVAC systems.

REPOST: Cooling has key role in building energy

RAC editor Andrew Gaved gives emphasis on what the cooling industry can do to help improve building energy efficiency.

Image Source: blogs.law.columbia.edu

The subject of energy seems to be being talked about nonstop at the moment – from attempts to rein in suppliers to the risk of the Grid reaching capacity to, of course, the rising cost of the stuff.

We have thrown our two penn’orth into the debate by way of our first Building Energy Question Time (see RAC January issue). It was a fascinating discussion which had in about equal parts good news for the industry, depressing news for the industry and challenges for us to rise to.


As is traditional, here’s the bad news first: there is a clear sense that much of the regulation surrounding energy isn’t working, for either the supply chain or for customers. At the Question Time, panellist after panellist talked about regulations that were missing the mark, whether it be Green Deal, which has expensive interest rates, deterring take-up; Part L, which has dropped the consequential improvements element so crucial to keeping heat in a building; or Energy Performance Certificates, and the woeful take-up of the air conditioning inspections – the mandatory inspections remember – which were supposed to help building owners improve energy efficiency.

Image Source: cooling4industry.co.uk

However, the good news is that the cooling industry can play a major role in improving building energy. Former Cibse president Andy Ford painted a particularly compelling picture of using ground source heat pumps to manage heating and cooling across a year, to the extent of linking buildings that have a heat need with those that have cooling. As he wryly noted, this approach ‘introduces the idea that cooling is actually good – not wicked as many green people seem to think’. I hope Ecobuild and its speakers have taken note.


The main challenge is to galvanise our industry to take on these opportunities, and to shout louder than some of the other noisy lobby groups to convince government we have some of the solutions to reducing buildings energy. We will be returning in 2014 with another Buildings Energy debate, so watch this space.


The other thing that a lot of people are talking about (still) is the fallout from the demise of WR Refrigeration and what the industry might be able to learn from it. There has been reaction from across the industry to the opinions of Kelvin Lord in last month’s issue, and we carry some of the responses, as well as a counterpoint from Thermacom’s Trevor Dann in the January issue.

Image Source: ecofriend.com

One of the overarching themes is that the retail contractors’ margins are becoming too low to be sustainable. Doing something about this is of course the big challenge – it has been suggested the only reason retailers get away with consistently driving down prices is because no one is standing up to them. But it isn’t quite as simple as that when the buying team across the desk holds the power over 30 per cent of your business. Or more.


What the industry doesn’t need is for the WR debate to increase tension between contractors and customers. Because now, perhaps more than any other time for decades, the supply chain needs to pull together to meet the demands of a reduced emissions, reduced energy future.

Hobson Air Conditioning Inc. is a full-service air conditioning and heating contractor based in Texas. Visit this website to learn more about its products and services.