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Ground-Source Heat Pumps (2009)

first_imgNo matter the configuration, the actual heat exchange in the heat pump usually happens in a unit inside the house. It is here that a refrigerant alternately evaporates and condenses and heat is transferred either into or out of the air being circulated through ducts to warm or cool the house. In a slight variation of this, “direct-exchange” ground-source heat pumps have the refrigerant flow through copper tubing that is buried, so the heat exchange is more direct; I won’t get into the specifics of how these systems differ.The big advantage of ground-source heat pumps is higher efficiency—somewhat higher than air-source heat pumps and much higher than electric-resistance heat. The disadvantage is cost. In our area, a typical ground-source heat pump may cost $35,000 or more; I have heard of local houses where systems costing as much as $70,000 were installed.This gets back to a point I made last week—and often make. In new construction, I believe that it makes a whole lot more sense to take a chunk of the money that would be spent on an expensive heating system—whether a ground-source heat pump, a radiant-floor heating system, or a high-tech European pellet boiler—and instead put that money into the house envelope.If you’re considering a $35,000 ground-source heat pump, take $30,000 of that and put it into R-40 walls, R-60 ceilings, R-30 foundations, careful air sealing, and triple-glazed windows with two low-e coatings. By doing this, you’ll get your heating loads down so low that a much simpler heating system can satisfy your needs and provide perfectly adequate comfort. That heating system might be a through-the-wall-vented gas space heater, a pellet stove, electric-resistance baseboard heat, or an air-source heat pump, such as the new-generation “mini-split” systems that I’ll cover next week.In new houses where only standard insulation levels are planned (R-20 walls, R-40 ceilings, and double-glazed low-e windows, for example) and with existing houses, the heating loads will be much higher, so spending a lot of money for a highly efficient heating system can be justified. In this situation, a ground-source heat pump may make sense. Ground-Source Heat Pumps (2010)GBA Encyclopedia: Heat Pumps: The BasicsGBA Encyclopedia: Green Heating OptionsAre Affordable Ground-Source Heat Pumps On the Horizon?Podcast: Ground Source Heat Pumps, Part 1: The BasicsPodcast: Ground-Source Heat Pumps, Part 2: Rules of ThumbPodcast: Ground-Source Heat Pumps, Part 3: Five QuestionsGround-Source Heat Pumps Don’t Save EnergyGround-Source Heat Pumps Have Low Operating CostsIs a Ground-Source Heat Pump a Renewable Energy System?Air-Source or Ground-Source Heat Pump?Heating a Tight, Well-Insulated House RELATED ARTICLES center_img Last week I introduced heat pumps and described how they can deliver more heat than is contained in the electricity they consume—while being able to provide cooling as well as heating. I mentioned two different types of heat pumps: air-source and ground-source. This week I’ll cover ground-source (also known as “geothermal” and “geo-exchange”) heat pumps.All heat pumps rely on a “heat source” during the winter months and a “heat sink” in the summer where unwanted heat can be dumped. While air-source heat pumps use the outside air as the heat source and heat sink, ground-source heat pumps use the ground, or sometimes a body of water, for these functions.The advantage of using a ground source for this heat exchange is that temperatures more than five feet underground are much warmer than the outside air during the winter and much cooler than the outside air during the summer, so the heat pump operates more efficiently. Put a different way, there’s more heat to extract from this source in winter, and there’s a greater capacity to absorb unwanted heat in the summer.Some ground-source heat pumps have “closed loops” of buried tubing through which fluid is circulated—either water or a water-antifreeze solution—to exchange heat with the ground. This tubing can either be laid in horizontal trenches or vertically in wells, depending on the land area available and the character of the soils or rock. (With a water-source heat pump—a specialized type of ground-source heat pump—a coil of tubing typically sits in the water.) Some heat pumps have “open loops” in which water from a well or lake is pumped to the house, and then returned after the heat-exchange process.last_img read more

Grizzlies fire coach J.B. Bickerstaff, reassign GM to scout

first_imgSports Related Videospowered by AdSparcRead Next DA eyes importing ‘galunggong’ anew “No words,” Grizzlies veteran point guard Mike Conley wrote on Twitter.Memphis began this season with Wallace predicting the Grizzlies would be a playoff team.The Grizzlies wound up trading away center Marc Gasol at the trade deadline. With other trades and injuries that left nine rotation players benched with injuries for Wednesday night’s season finale in a 132-117 win over Golden State, Memphis tied its own NBA record for most players used in one season — set last season — again at 28.Memphis also set the NBA mark with 20 different leading scorers, topping the old record of 16 set by the Knicks in 2014-15.While Memphis kept Conley after a frenzy of speculation about his future before the trade deadline, that chatter is about to start again. And Conley, 31, sounds ready to consider his best interest about what happens next with Memphis in full-blown rebuilding mode.ADVERTISEMENT Wallace had said earlier that Bickerstaff would be returning after doing a “terrific job.” But Pera didn’t agree and restructured the front office a few hours later.“In order to put our team on the path to sustainable success, it was necessary to change our approach to basketball operations,” Pera said in a statement. “I look forward to a re-energized front office and fresh approach to Memphis Grizzlies basketball under new leadership, while retaining the identity and values that have distinguished our team.”FEATURED STORIESSPORTSPrivate companies step in to help SEA Games hostingSPORTSPalace wants Cayetano’s PHISGOC Foundation probed over corruption chargesSPORTSSingapore latest to raise issue on SEA Games food, logisticsBickerstaff was named interim coach in November 2017 after the Grizzlies fired David Fizdale . He was given the job without the interim title last May. Now Memphis is looking for a fourth head coach since choosing not to renew Lionel Hollins’ contract after he led the Grizzlies to their lone Western Conference final appearance in 2013.The Grizzlies also announced that Jason Wexler will be president of the Grizzlies overseeing both basketball and business operations, and Zachary Z. Kleiman replaces John Hollinger as executive vice president of basketball operations with Hollinger moving to an advisory role. The Grizzlies are keeping former player Tayshaun Prince as a special adviser. FILE – In this a, Memphis Grizzlies head coach J.B. Bickerstaff reacts in the second half of an NBA basketball game against the Denver Nuggets in Denver. The Grizzlies fired Bickerstaff on Thursday, April 11, 2019. (AP Photo/David Zalubowski, File)MEMPHIS, Tenn.— The Memphis Grizzlies started the offseason Thursday with plenty of questions to answer, then controlling owner Robert Pera added to the to-do list by firing coach J.B. Bickerstaff as part of a front-office shake-up that demoted general manager Chris Wallace to scout.The Grizzlies announced the moves after both Bickerstaff and Wallace spoke to reporters following a second straight season outside the playoffs. After a 12-5 start, Memphis plummeted and finished 33-49, tied with New Orleans and Dallas.ADVERTISEMENT Cavs begin coaching search after parting ways with Drew Hontiveros presses for security audit of national power grid Panelo: Duterte ‘angry’ with SEA Games hosting hassles PH underwater hockey team aims to make waves in SEA Games PLAY LIST 02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City01:07Trump talks impeachment while meeting NCAA athletes02:49World-class track facilities installed at NCC for SEA Games02:11Trump awards medals to Jon Voight, Alison Krauss MOST READ Don’t miss out on the latest news and information. Ethel Booba twits Mocha over 2 toilets in one cubicle at SEA Games venue SEA Games hosting troubles anger Duterte Cayetano: Senate, Drilon to be blamed for SEA Games mess LATEST STORIES Philippine Arena Interchange inaugurated Private companies step in to help SEA Games hosting “I honestly don’t think that would be the ideal situation,” Conley said. “Ideally, I don’t think anybody in my situation would want to go through that again, (since) I don’t know how many years I have left.”Conley helped his potential value by averaging 24 points and 6.5 assists over his final 16 games. Conley still has two seasons left on the max deal he signed in July 2016,.“I’m pretty much getting ready for it, getting ready for that storm …,” Conley said of the coming speculation. “In the last few weeks, it’s become more and more like knocking on the door. It’s right around the corner. This stuff is going to fire up again. Rumors, all that stuff is going to pop up.”Wallace oversaw the signing of Chandler Parsons to a four-year, $94 million deal that has seen the forward play 95 games combined over the first three seasons.The Grizzlies spent much of the season trying to finish outside the top eight spots in the draft to finally pay off a 2015 midseason trade for Jeff Green that still requires a first-round pick to be sent to Boston. The selection is protected if Memphis finished anywhere from No. 1 to 8 in the draft, and the Grizzlies want to fulfill that obligation this June.Memphis wound up in a three-way tie with Dallas and New Orleans for the 7-9 position. Whether the Grizzlies land in the ninth position or with the selection protected won’t be known until after the May 14 draft lottery.The next Grizzlies coach will have Jaren Jackson Jr. who showed flashes as the fourth overall draft pick last summer before a deep thigh bruise sidelined him after 58 games. Dillon Brooks also was limited to 18 games by injuries, and Kyle Anderson, signed to a four-year deal last summer, played only 43 games and will have surgery next week on his right shoulder.Jonas Valanciunas, acquired in the February trade for Gasol, has a $17.6 million player option next season. View commentslast_img read more