{"id":821,"date":"2016-05-14T08:23:41","date_gmt":"2016-05-14T12:23:41","guid":{"rendered":"http:\/\/blog.uvm.edu\/cwcallah\/?p=821"},"modified":"2016-05-21T16:16:11","modified_gmt":"2016-05-21T20:16:11","slug":"pumps-and-pipes","status":"publish","type":"post","link":"https:\/\/blog.uvm.edu\/cwcallah\/2016\/05\/14\/pumps-and-pipes\/","title":{"rendered":"Pumps and Pipes"},"content":{"rendered":"
\"A<\/a>
A Taco 007, shaken not stirred.<\/figcaption><\/figure>\n

“Will the 007 be enough?”\u00a0 is a common question in early spring as greenhouses around the region fire up and we do our best to keep seed trays and their cargo warm on the still-cool nights.\u00a0 My mind instantly goes to “which movie?” And then I crash back to earth and realize this is a question about pumps and I am not Q.<\/p>\n

The 007 is a very common circulator from Taco that we all seem to have among our midden heaps. Wire up some power and thread some pipe into the never-easy-to-find pipe flanges and you’re in business.\u00a0 But will that pump do that job? Just how much flow (gallons per minute, GPM) will result if a certain size line is used?\u00a0 What if I have 86 elbows in the line?<\/p>\n

Many times I’m asked to help farmers and processors select a pump or size piping for a specific need.\u00a0 Common applications include bench heating in a greenhouse, running hot water from a boiler to a hot water unit heater, making use of “that old spring up on the hill”, or setting up a solar irrigation system.<\/p>\n

We’ve been moving water for years<\/a>.\u00a0 In the summer I love watching my young son and his friends play with water at the beach.\u00a0 Ok, I’ll admit it.\u00a0 I’m in the thick of it.\u00a0 I’m building the holding ponds and canals of sand.\u00a0 I’m supervising the “bucket crews” to ensure we have steady flow.\u00a0 “We need this ‘fish pond’ deeper over here!\u00a0 Let’s keep Sparky happy.”\u00a0 “We’ve got a break in the wall over there!”<\/p>\n

We love moving water, and that is a really good thing.\u00a0 Because life depends on it<\/a>. I love thinking about pumps and piping and how they play together to do good, honest work for us. The key thing to remember is that flow requires pressure difference; water only moves from one place to another because there is a difference in pressure.\u00a0 Water flows downhill because of “head” pressure created by gravity that acts on the “column” of water.\u00a0 The same thing happens with a human pyramid. A column of water can’t support itself, of course, so it gives way and flows down to where it collects, drains or otherwise moves on.<\/p>\n

When I was first introduced to a pump curve I thought is was one of the most amazing things on earth.\u00a0 It brought some certainty and predictability to an otherwise mysterious process.\u00a0 A pump curve is a characteristic relationship of flow and pressure for a given pump (running at a certain speed).\u00a0 Typically it is an actual “curve” plotted in graphic form with flow on the horizontal (X) axis and pressure head plotted on the vertical (Y) axis.\u00a0 It can also be presented as a table of data.\u00a0 A pump generates the highest pressure “head” when there is no flow, and generates the most flow when there is no pressure required.\u00a0 Both of these cases are purely theoretical, all real applications lie somewhere in the middle since flow with no pressure head and pressure head with no flow don’t do anything useful for us.\u00a0 The pump curve helps us know what is going on in the middle so that we can put the pump to use.<\/p>\n

The pump curve has a very close friend, the “system curve”.\u00a0 Just as flow doesn’t happen without pressure difference.\u00a0 It also doesn’t happen without pressure loss.\u00a0 The flow of water in a pipe or channel creates friction at the edges.\u00a0 This is why the velocity of a stream or river is higher in the center then it is on at the bank.\u00a0 Luckily for us, this is also a fairly predictable thing<\/a> if we know something about the fluid being moved, the pipe dimensions and the rate of flow.\u00a0 So pumps and their systems do a dance and find a happy balance of flow and pressure that they can agree on.\u00a0 My friend Ben <\/a>and I provided a summary of how to use pump and system curves in our article about solar irrigation systems<\/a>.<\/p>\n

When we wrote that article it felt great that we had compiled this information and provided it in a concise article, but I also felt there was more that we could do to help folks “navigate the waters” of pumps and pipes.\u00a0 I know from my own experience that trying to track down pipe dimensions and pump curves is a time consuming and frustrating process.\u00a0 It is challenging even before you get into the math involved in putting the two curves together.\u00a0 So I wanted to make this process easier by creating the pump and pipe calculator<\/a>.<\/p>\n

\"Pump<\/a>
Pump and Pipe User Interface Screen.<\/figcaption><\/figure>\n

This calculator has a list of common circulation pumps used for smaller volume systems common on Vermont farms.\u00a0 I have taken their pump curves and put them into the calculator so you don’t have to look anything up.\u00a0 Similarly, I have compiled the dimensions of common piping and tubing in the calculator as well.\u00a0 You enter what you know about the flow required (gallons per minute or GPM).\u00a0 If you know a heat rate (BTU\/hr) and temperature change it will calculate the required GPM for you. You also enter what you know about the piping but selecting the pipe type and size and providing some basic information about length of run.\u00a0 All the math is done for you and a simple graph of both pump curve and system curve is presented with two points added on.\u00a0 The first point added on is the the operating point your inputs resulted in (GPM and pressure in “feet head of water”).\u00a0 The second point added is the intersection of the pump and system curves.\u00a0 This is the likely point of operation for the combined system.\u00a0 Based on the difference between these two points, you can adjust you pump and pipe selection until the two points align.<\/p>\n

\"Sample<\/a>
Sample plot of pump and system curves from the Pump and Pipe Calculator.<\/figcaption><\/figure>\n

I hope you find this new tool helpful and ask that you provide feedback to help improve it<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

“Will the 007 be enough?”\u00a0 is a common question in early spring as greenhouses around the region fire up and we do our best to keep seed trays and their cargo warm on the still-cool nights.\u00a0 My mind instantly goes to “which movie?” And then I crash back to earth and realize this is a … <\/p>\n

Continue reading “Pumps and Pipes”<\/span><\/a><\/p>\n","protected":false},"author":1174,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[6522,50620,6519,684047],"tags":[],"class_list":["post-821","post","type-post","status-publish","format-standard","hentry","category-equipment","category-greenhouses-2","category-heating","category-energy-on-the-farm","entry"],"featured_image_src":null,"featured_image_src_square":null,"author_info":{"display_name":"Chris Callahan","author_link":"https:\/\/blog.uvm.edu\/cwcallah\/author\/cwcallah\/"},"_links":{"self":[{"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/posts\/821","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/users\/1174"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/comments?post=821"}],"version-history":[{"count":7,"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/posts\/821\/revisions"}],"predecessor-version":[{"id":843,"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/posts\/821\/revisions\/843"}],"wp:attachment":[{"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/media?parent=821"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/categories?post=821"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.uvm.edu\/cwcallah\/wp-json\/wp\/v2\/tags?post=821"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}