Choosing a New HVAC System

first_imgGetting accurate heating load estimates“Manual J” is a protocol developed by the Air Conditioning Contractors of America to produce accurate estimates of peak heating and cooling demands based on the characteristics of a particular house. The procedure is widely recommended, but Dorsett says that HVAC contractors rarely use it and, he adds, “only a fraction of those will perform [it] correctly.”It would be better if Jill hired a RESNET rater or an engineer. Or, he adds, Jill could use previous gas bills and weather history data to calculate whole-house heating loads herself, a process he describes as “not very time consuming.” (For more on how to do that, read this article.)“In a zone 5B climate with ‘a lot of southwest glass for passive heat,’ the fuel-use load calculation may hit somewhat to the low side,” Dorsett says, “but not more than 20% unless the house had been meticulously designed for solar tempering, including optimizing the specifications for the low-e coating. Run the fuel-use load calculation, see how it stacks up against the Cool Calc freebie numbers. The fuel-use load numbers will almost certainly come in substantially lower, no matter what reasonable heating-degree day (HDD) base temperature is used.” Jill has been looking around for an HVAC contractor but so far hasn’t settled on one. “I’m not getting great proposals,” she says. One refused to do Manual J and Manual D calculations, which are typically recommended as the necessary first step to specifying HVAC equipment. Another is willing to take Jill’s suggestions, but doesn’t seem to know which system would be the most energy-efficient.In other words, she’s stuck, and that’s that’s the story behind this Q&A Spotlight. Using the furnace fan for filtrationOne of Jill’s goals is to have an efficient furnace fan that would be used to mix air in the house as well as provide some filtration. Her thermostat has a setting that runs the fan for about 10 minutes an hour at a less-than-maximum speed. It doesn’t increase her power bill significantly, and it seems to help with Jill’s seasonal allergies.But, Dorsett warns, no matter how efficient the furnace fan might be, using it that way is “extremely inefficient.” Instead, he suggests a heat-recovery ventilator set up to recirculate air would be more appropriate.He adds that modulating ducted heat pumps are probably not the answer, either. Most don’t have extended temperature capacity tables that go below -4°F, he says, and many don’t go that low.“They also don’t have turn-down ratios more than about 2.5:1 (at minimum speed they’re still delivering fully 40% of what it would deliver at maximum speed, no matter how many incremental steps it has), so very accurate load calculations and careful sizing is required for them to hit their high HSPF and SEER efficiency numbers,” Dorsett says.Plus, he says, the air handler for a ducted heat pump uses 10 times more electricity than an HRV in recurculation mode. “So even running a 100% duty cycle on the HRV uses less power than cycling the heat pumps air handler for 10 minutes per day.” Yes, a ductless minisplit could handle the coldOne key question is whether a ductless minisplit would be capable of heating Jill’s house in the dead of winter without some type of backup heat. On that issue, Holladay has no doubt she would be fine: “The contractors who are telling you that Climate Zone 5 is too cold for ductless minisplits are not telling the truth.”Dana Dorsett adds that it’s possible to heat with minisplits even when the temperature drops to 25 below zero Fahrenheit. In Climate Zone 5B, he says, a correctly sized minisplit can equal the seasonal efficiency of a ground-source heat pump.Several years ago, he writes, the Northwest Energy Efficiency Alliance monitored the performance of minisplits in Climate Zones 4C to 6B and found that even older designs functioned well, performing with an average COP of nearly 3. (There’s more on that study here.)“The typical name-plate HSPF (heating seasonal performance factor) of those units of old was about 10.0 Btu/watt-hour,” Dorsett says. “Current model ductless minisplits designed for cold climates are now testing in the HSPF 13s and 14s. If the units are sized optimally, you should be able to beat the efficiency performance of the field survey units monitored by the NEEA in the 2010-2011 time frame.”He adds that living in a “B” zone (a dry region of the country in the West) means that a heat pump would use less energy in defrost cycles. And there’s little or no latent cooling load.Adds Calum Wilde: “Climate Zone 6A here. We had close to two weeks of approximately 0-5°F. My ductless minisplits worked great, they easily kept the house at 68°F.” RELATED ARTICLES Let’s do the mathIn replying to a question from GBA editor Martin Holladay, Jill says that the cost of electricity in her area is about 10 cents per kilowatt-hour, while gas is between 47 cents and 50 cents a therm. Based on those numbers, Holladay says, the most economical choice will be natural gas. In a furnace running at 80% efficiency, 100,000 Btu of energy would cost 63 cents. That compares with 98 cents for a heat pump with a coefficient of performance of 3, and $1.47 for a heat pump with a COP of 2.“When it comes to cost, gas wins,” Holladay says.Gas, however, isn’t Jill’s first choice even if it’s less expensive than other options now.“Gas won’t be cheap forever and doesn’t play well with solar (planned, none yet),” she says, “and [it] supports fracking (a problem in my area).”Instead, she wonders whether a heat pump with an inverter, capable of running at different speeds, or a Trane modulating furnace might be a better answer. Saving Energy With Manual J and Manual DHow to Perform a Heat-Loss Calculation — Part 1How to Perform a Heat-Loss Calculation — Part 2Calculating Cooling LoadsWho Can Perform My Load Calculations?Out With The Old, In With The NewGreen Basics: Green Heating OptionsHow To Buy a Ductless MinisplitRules of Thumb for Ductless MinisplitsJust Two Minisplits Heat and Cool the Whole HouseReport on Our Ductless Minisplit Heat Pump Our expert’s viewGBA technical director Peter Yost added these thoughts:Three of the conditions mentioned by Jill D strike me as important:Lots of southwest-facing glass that creates problems in the summer.A desire to filter indoor air with the HVAC system.The fact there are three distinct heating and cooling zones in the house.Jill D has a tall order. She wants to improve HVAC efficiency, deal with summertime solar gain, improve air quality, configure new systems so they can accommodate a photovoltaic system in the future, and integrate domestic hot water, if possible. The only conditioning not included in this mechanical system Rubik’s cube is dehumidification.It would be hard enough to solve this entire puzzle in new construction; in a retrofit, it’s just too much. Here are my suggestions:Keep looking for a qualified HVAC contractor or mechanical engineer. Your project seems well beyond the skills of the folks you’ve been dealing with so far.Tackle the issue of domestic hot water separately.Address summertime solar gain with shading. This is particularly true in a dry climate.Address air quality with a whole-house mechanical ventilation system. It’s hard to deal with allergies without whole-house mechanical ventilation. (For more information, see this article by Brian Just. It’s possible to use CO2 levels as a proxy for indoor air quality.)Stick with ductless minisplits as a solution to your three-zone problem.I hate to end with something that might seem like a crackpot idea, but I’d like to think that somewhere out there you could find a high-efficiency, cold-climate, air-to-water heat pump system that will integrate hydronic space heating, domestic hot water, and (at least for some of Climate Zone 5B) even space cooling. It might be something along the lines of this new unit from Nordic Heat Pumps. I have heard whispers of this and am pursuing it; but so far, I have nothing solid to share. Stay tuned. Jill D has done her homework, and now it’s time to choose a new heating and cooling system for her Climate Zone 5B home.There are three distinct zones to consider: the main house, a sunroom addition, and an office addition. Neither the office nor the sunroom is ducted, although heating and cooling loads there are relatively low. In the main house, the heating load has been calculated at between 28,000 and 36,000 Btu per hour, and the cooling load at between 24,000 and 36,000 Btu per hour.Jill’s existing furnace, which she estimates is 10 years old, is a 115,000 Btu/h variable-speed unit. Cooling is provided by a pair of 1-ton minisplits that have proved expensive to run. The existing water heater is near the end of its life.What Jill has in mind is efficient central cooling with a blower that can run in circulation mode for filtration and to even out temperatures around the house. She’d like a system that’s sized correctly so it doesn’t cycle on and off frequently, and something that will provide cooling in her office.“I’ve thought about minisplits or just an electric heat pump,” she writes in a post in the Q&A Forum, “but everyone says the climate is just a little cold with no backup heat and that minis are the most expensive option. There is a lot of southwest glass for passive heat in the winter but it’s problematic for summer.”last_img read more

Caregivers Battling Suicide on the Homefront

first_imgBetween 2005 and 2010, approximately one service member died every 36 hours, not by Afghanistan or Iraq insurgents, not from a result of a training exercise or automobile accident–but from suicide.In 2009 alone, 160 active duty military personnel took their lives, making suicide the third leading cause of death among the Army population (Army HP/RR/SP Report, 2010).As more troops return home from deployment, the risk of suicide may grow. It is important that families of these service members become aware of the issue and learn to identify potential risk factors and warning signs associated with suicide. Remember, as a caregiver–the more you know, the more you are likely to provide proper care and provide the immediate attention your service member needs and ultimately prevent the loss or injury of your loved one.Understanding Suicide PreventionRisk FactorsSeveral factors may be taken into account for someone to attempt or commit suicide. As a military caregiver, you should become aware of these risk factors associated with suicide.Failed intimate relationship or relationship strainFamily history of suicide or suicide attemptsHistory of depression or other psychological issuesSignificant loss (death of loved one or fellow service member within unit)Drug or alcohol abuseViolence in the home or social environmentRecent disciplinary or legal actionsSerious medical problems or physical illnessWork-related problemsExcessive debt and other financial problemsWarning Signs of Potential SuicideIf you notice substantial changes in your loved one’s demeanor since he or she has returned home from combat, he or she may be exemplifying signs of potential suicide.  The following warning signs may lead you to indicate that your service member is suicidal:Changes in eating, sleeping habits, or personal hygieneTalking or hinting about committing suicideExpressing a strong desire to kill someone elseObsession with death (for example, in music, poetry, artwork, letters)Changes in mood (for example, depression, irritability, rage, anger)Increased alcohol and/or drug use or abuseIsolation and withdrawal from social situationsGiving away possessionsExpressing feelings of sadness, hopelessness, anxietyMaking a will or otherwise finalizing personal affairsProblem with spouse or partnerSudden or impulsive purchase of a firearm or obtaining other means of killing oneself such as poisons or medicationsCaregiving StrategiesAs a military caregiver, it can be hard to admit to yourself that your service member may be displaying signs of suicide. However, in today’s society where suicide has increased dramatically since the start of the global war on terrorism, many service members are at risk. In addition to identifying risk factors and warning signs, there are strategies that you, as the caregiver can do to help your loved one and yourself get thought this difficult time.Look for any signs that show a deviation from your service member’s usual self.Get help immediately! A suicidal person needs immediate attention.Do not keep your warrior’s suicidal behavior a secret.Do not ignore the situation and hope that things will eventually get better.Talk openly about suicide. Be willing to listen and allow your loved one to express his/her feelings.Actively listen for details about what, where and when your service member may be planning on killing himself or herself.Actively listen without passing judgment.Stay calm and safe–do not use force.Provide a comforting and relaxing atmosphere.Never leave the service member alone.Escort warrior to his/her chain of command immediately.Understand that your loved one may be in pain.Remove any means that could be used for self-injury (for example, weapons or pills).Provide your service member with contacts for suicide prevention (for example, a chaplain or behavioral health professional).Be in control of the service member’s medications.Be aware of how the service member’s behavior is affecting any children in the household.Consider individual and family therapy.Ask your service member’s doctors or nurse case manager on information regarding suicide and mental illness.Seek spiritual healing.Take care of yourself!Caregiver ResourcesIf your loved one is experiencing thoughts or symptoms of suicide–do not hesitate, call the Veterans Crisis Line at 1-800-273-TALK (8255) for immediate assistance.Also, contact your local Army installation’s Soldier and Family Assistance Center (SFAC) for support groups and caregiver support services.For more information on suicide within the military, visit the Army Suicide Prevention Program. The program offers a variety of information and resources relating to suicide in order to improve readiness for service members and their families.last_img read more

Intelligence Bureau denies bugging in Finance Minister’s office

first_imgPranab Mukherjee clarified that no bugging device has been found in initial probe by IB.The Intelligence Bureau has denied that the finance minister’s office was bugged. IB sources said the security and intelligence agencies carry out a four-level check for at least key ministries on Raisina Hills — Defence, Home, MEA and Finance. The drill includes shadowing of key officials, which was done in case of Ravi Inder Singh, Director of Internal Security in the Home Ministry. Singh was arrested a few months ago. Cell phone calls of key officials are also monitored. Hard disks of computers of officials handling sensitive charges are scanned. Electronic sweeps are also part of the security drill. IB sources told Headlines Today that they conducted a through probe into the complaint that several offices, including that of Finance Minister, were bugged. Sources said it seems to be a case of false alarm. No bugging devices have been found in the initial probe, a fact that Finance Minister Pranab Mukherjee himself has confirmed. “Regarding the bugging in my office?I would like to clarify that IB probed, but found nothing,” Mukherjee said on Tuesday.FM urged probe Mukherjee had urged Prime Minister Manmohan Singh to undertake a secret probe to look into the attempt to bug his office. Fears of a breach in Pranab’s office surfaced after taxmen and security agencies found as many as 16 adhesives strips planted in North Block offices of the Finance Minister and his officials. The adhesive strips were found in the offices of Pranab’s advisor, personal secretary and two conference rooms.  Pranab wrote a letter in September 2010 to prime minister asking him to order a secret probe. The Central Board of Direct taxes also conducted electronic sweeps.  The CBDT is particularly alarmed that the surface of the strips had grooves, which suggested planting of tiny devices that have been pulled out later. The CBDT chairman has also confirmed to Headlines Today about these adhesive strips.advertisementOpposition attacks govt Launching an attack on the UPA, the BJP said on Tuesday “this is a non-functioning government”. “The UPA government has lost its way. Things have reached such a pass that Pranab suspects that his office is bugged. Who is doing this? The fact that a private company was investigating suspicions of bugging indicates that the FM has no faith in Home Minister P. Chidambaram,” BJP spokesperson Shahnawaz Hussain said. “There is civil war underway within the government and between ministers. This is a serious issue. People want to know who is snooping on the FM. Pranab has no faith in his home minister. This is a non-functioning government. Senior leaders within the party are sparring against the PM. The Congress president needs to reply what is the party’s stand on the matter,” Shahnawaz added. “These things are quite possible in the given situation. The Finance Ministry is the most sensitive ministry. Economics is the real politics today. There’s cut-throat competition with corporate houses working at cross-purposes and trying to influence policies,” CPI leader D. Raja said.  Raja added, “You come across such bugging n American thrillers. Now for the first time, you hear of something like this vis-a-vis our own government. Pranab must have had some serious doubts. Otherwise, why would he take it up with the PM? Some people say it was only chewing gum. But why was it everywhere? There is something dubious. It shows some serious situation that is emerging in the country.”  Senior BJP leader Mukhtar Abbas Naqvi said, “Bugs in the FM office is a serious issue. The government should clarify who is responsible – ASAP – when there are serious cases of economic offences.”For more news on India, click here.For more news on Business, click here.For more news on Movies, click here.For more news on Sports, click here.last_img read more