Subscribe 11 recommended0 commentsShareShareTweetSharePin it faithfernandez More » ShareTweetShare on Google+Pin on PinterestSend with WhatsApp,Virtual Schools PasadenaHomes Solve Community/Gov/Pub SafetyPASADENA EVENTS & ACTIVITIES CALENDARClick here for Movie Showtimes Your email address will not be published. Required fields are marked * Business News Top of the News Name (required) Mail (required) (not be published) Website First Heatwave Expected Next Week EVENTS & ENTERTAINMENT | FOOD & DRINK | THE ARTS | REAL ESTATE | HOME & GARDEN | WELLNESS | SOCIAL SCENE | GETAWAYS | PARENTS & KIDS “Helping you live your dreams”As a child growing up in the San Rafael area of Pasadena, Christmas was my favorite time of the year. The San Gabriel Valley would sparkle with Christmas lights and our mother knew just where to take us to see the best displays. We would pile into the family station wagon and tour St. Albans Road, Christmas Tree Lane, the Balian Mansion and Hastings Ranch.But my favorite excursion was to Bullockâ€™s on South Lake to have my photo taken with Santa. After confiding my most heartfelt desires, I would head across the street to Blumsâ€™s, with my siblings, where my mother said we could each order a hot fudge sundae or a banana split.Today I work on South Lake Avenue, right down the block from where Blumâ€™s was located. And, as a Pasadena-born-and-bred realtor, I know all the best chimneys in town. If you live in the San Gabriel Valley you can trust me to find you the perfect chimney for Santa to use to deliver your presents to you in the future. And, donâ€™t forget to have hot cocoa and cookies ready for him, like we did onÂ Christmas Eve at the Bell house. Pasadena’s ‘626 Day’ Aims to Celebrate City, Boost Local Economy Community News More Cool Stuff center column 3 Christmas Memories… A Soliloquy By ROSEY BELL Published on Tuesday, December 10, 2013 | 11:42 am Get our daily Pasadena newspaper in your email box. Free.Get all the latest Pasadena news, more than 10 fresh stories daily, 7 days a week at 7 a.m. Community News Make a comment Pasadena Will Allow Vaccinated People to Go Without Masks in Most Settings Starting on Tuesday Herbeauty10 Sea Salt Scrubs You Can Make YourselfHerbeautyHerbeautyHerbeautyHere Is What Scientists Say Will Happen When You Eat AvocadosHerbeautyHerbeautyHerbeauty5 Things To Avoid If You Want To Have Whiter TeethHerbeautyHerbeautyHerbeauty9 Hollywood Divas Who Fell In Love With WomenHerbeautyHerbeautyHerbeauty8 Easy Exotic Meals Anyone Can MakeHerbeautyHerbeautyHerbeautyHe Is Totally In Love With You If He Does These 7 ThingsHerbeautyHerbeauty Home of the Week: Unique Pasadena Home Located on Madeline Drive, Pasadena
Manchester United’s winning start to the season has come to an end after they were held to a 0-0 draw by Newcastle United at Old Trafford.Wayne Rooney is now 10 games without a goal in a red shirt, but it wasn’t for the lack of trying as he had an early effort incorrectly ruled out for offside.But Louis van Gaal will be frustrated as compatriot Tim Krul denied several efforts from Juan Mata and Memphis Depay as the Magpies held on, despite initial looking like they would struggle.After a stunning performance in midweek against Champions League opponents Club Brugge, Depay looked to impress again but an early shot rolled tamely into Krul’s arms, while Rooney had his goal ruled out just four minutes in.Krul was test again just seven minutes later but he was able to comfortably catch a Juan Mata free-kick after Ayoze Perez had ended a Matteo Darmian run with a mistimed tackle.The Dutch goalkeeper was again forced into a good save from the Spaniard when he was allowed to much time in the box by some poor defending, before Rooney, again with too much time, shot straight at him.While Matteo Darmian has looked solid for Manchester United he also looks clumsy in the tackle and swiftly found himself cautioned as he took down Massadio Haidara, who was charging up the left flank. The Toon star was then booked himself for a late challenge on Daley Blind.Depay looks set to dazzle the Premier League and an excellent piece of skill set himself free in the box but his shot was poor again.The Magpies rallied late in the first period and after Aleksander Mitrovic hit the bar with a header from Chancel Mbemba’s cross and Perez’s drive from range was tipped around the post by a sprawling Sergio Romero, with the following corner causing havoc in the United penalty area.In the second half the Red Devils picked up where they left off but their lack of cutting edge up front was telling.Depay crashed a free-kick into the wall, while several chances and set-pieces went begging and even with Javier Hernandez joining Rooney up front they could not carve open a solid Magpies backline who have clearly been well drilled since a couple of shaky performances.And just when Hernandez had managed to stumble his way into the penalty area he was denied by Krul’s outstretched leg.As time ticked on, a close range volley from Antonio Valencia slammed in Fabricio Coloccini, while a Chris Smalling cracked the post while up for a corner.Newcastle United could have won the game with a late counter but after a team-mate twisted and turned in the box, debutant Florian Thauvin could connect with the cross as he slid in, leaving the match to end in a stalemate. 1 Manchester United are denied by Tim Krul
This is the second post in a 2-part series on the physics of moving air through ducts. If you missed it, click here for The Best Velocity for Moving air Through Ducts, Part 1. The first thing to know about the velocity of air moving through ducts is that the slower you get the air moving, the better it is for air flow. That was the main point of my last article. It asked the question, is low velocity bad for air flow in ducts? And the answer was that, in terms of air flow, you really can’t get the air moving through the ducts too slowly. But that’s not the end of the story. If it were, you’d always try to get the lowest velocity possible by using the biggest ducts that fit the space without blowing the budget. There’s another relevant fact, however, and ignoring it can lead to trouble.RELATED ARTICLESThe Best Velocity for Moving Air Through Ducts, Part 1The Continuity Equation and Air FlowDo High-MERV Filters Always Reduce Air Flow?Designing Duct System Vents for Good Air FlowIs It OK to Close Air Conditioner Vents in Unused Rooms? Second Law troubles In moving air through a duct system, we want good airflow, but remember that the object isn’t just to move air throughout the house. It’s to move heated air in winter and cooled air in summer. When that conditioned air is moving through the ducts, the second law of thermodynamics comes into play because we have a temperature difference between the inside and outside of the ducts. The second law of thermodynamics says that when you have objects at different temperatures, heat flows from the warmer to the cooler object. In winter, the warm air in our ducts can lose heat to the surroundings. In summer, the cool air gains heat from the surroundings. And the amount of heat that flows between the duct and its surroundings depends on three things: Surface area of the ducts Temperature difference between the ducts Insulation level (as given by U, the heat transfer coefficient, or R, the resistance to heat flow) The equation that ties these things together is: Q here is the rate of heat flow and the units we use for it here in the US are British thermal units per hour (BTU/hr). Heat transfer into moving air As the conditioned air moves through a duct, it gains or loses heat in proportion to those three factors. But that just tells you how many BTUs go into or out of the duct in an hour. The other factor is how much air is involved in picking up each BTU. The factor that governs this is velocity: The slower the air moves in a duct, the more BTUs each cubic foot gains or loses. And it’s not just time of contact that’s responsible. To get the air moving slower, we need bigger ducts so there’s more surface area, too. The upshot of all this is that when you’re sizing ducts, you have to consider the space those ducts are in. If you put ducts in conditioned space, you can move the air as slowly as you’d like. When you put the ducts in an unconditioned attic, you want to move the air at a higher velocity, pushing it up near the maximum recommended by ACCA Manual D, 900 feet per minute (fpm) for supply ducts and 700 fpm for return ducts. Mike MacFarland’s duct sizing tool My friend Mike MacFarland in Redding, California is a home performance and HVAC wizard. He knows the principles and has studied the research and he installs some of the best duct systems in the country. He uses the following ranges of velocity for ducts in different types of space: 600 to 750 fpm — Exposed ducts in unconditioned attics 400 to 600 fpm — Deeply buried ducts in unconditioned attics Less than 400 fpm — Ducts in conditioned space He put this into a chart that allows you to find the duct diameter that gives you the right velocity and air flow rate (cfm). The full chart covers duct sizes ranging from 4 inches to 18 inches and air flow rates from 0 to 1,200 cfm. (You can download the full chart by clicking on the image below or the link at the bottom of this article.) Here’s the bottom part of the chart, covering air flow rates up to 300 cfm: Mike MacFarland’s duct sizing tool. Photo: Mike MacFarland, Energy DocsIf you need a duct to move 100 cfm, for example, you’d go with a 7 inch duct if it’s in conditioned space, a 6 inch duct if it’s buried deeply in the attic insulation, and a 5 inch duct for exposed ducts in an unconditioned attic. The takeaway here is that low velocity is great for air flow but sometimes bad for heat transfer. By selecting duct sizes that yield velocities appropriate for the conditions, you get the best of both worlds. Download Mike MacFarland’s Duct Sizing Tool Allison Bailes of Decatur, Georgia, is a speaker, writer, building science consultant, and the author of the Energy Vanguard Blog. You can follow him on Twitter at @EnergyVanguard.