Hello. After some ideas on how to insulate hot water pipes. I presume the two types of heat loss I need to minimise are convective and radiant. My initial ideas have ranged from reflective roof sarking and gaffer tape to foam used in between concrete slabs and everything in between???
Not very scientific!! Must be a good alternative (pehaps something recycled??)
Have had a look in massive hardware conglomerate - not much that tickled my fancy
Any input would be most appreciated.
Cheers
Matt@ONE
Ideas for insulating hot H2O pipes
(26 posts) (10 voices)-
One
MemberPosted Thursday 5 Nov 2009 @ 9:47:16 am from IP # -
Bobthe...
MemberHi Matt
You didn't say what size and material the pipes are.
Normally 1/2" copper household pipes are lagged with a plastic sleeve, or polyurethane foam tube. Both are available with a split side seam, with a "ziplock" type closure.If that doesn't meet your requirements, then the concrete jointing foam strip might do.
If you wind it on in a helix..... for small pipes its probably too wide to get an easy wrapping helix, so you might split it lengthwise into 2 strips.
Once its wound on you only really need to secure joins and ends with duct tape.If the pipes are fitted close to walls or floors wrapping might be very difficult.
Laying a strip along the pipe and trying to secure it to the wall/floor might not be easy. Maybe a bead of polyurethane sealant at each edge could work if the pipe runs along in a corner..... or maybe a staple gun, depending on the adjacent material.Bob >>
Posted Thursday 5 Nov 2009 @ 10:19:53 am from IP # -
ghostgum
MemberArmaflex (polyurethane) pipe insulation or similar. You buy this from plumbing or some building supplies. It comes in a variety of sizes, and usually 2m lengths. It normally comes without a slit down the side, so to retrofit you either need to make a slit (sharp serated knife with a rounded end or tape over the end works well) or buy the variety with a slit down the side. I couldn't find anywhere that had the slitted variety in stock. I saw 1m lengths at Bunnings.
I rescued some from the skip when our house was being constructed, and added it to the hot water line to the kitchen. It does make a difference compared with bare plastic pipes, but isn't a huge difference. I think we lose more heat through the pipes in the instant gas heater. I added a slit to the foam lagging, and then used tied it back together with duct tape, with the slit on the bottom. It isn't fully sealed, but it stops most air movement around the pipe.
Your main heat loss is going to be conduction/convection.
Posted Thursday 5 Nov 2009 @ 11:11:14 am from IP # -
dymonite69
MemberI once did some basic calculations on this. For a PVC pipe - convective loss to radiant loss is about 3:2. Radiant loss is less from copper metal pipes.
Foil or white paint reduces the total heat loss by about a third
One inch foam lagging reduces total loss by about half.
Applying both reduces loss by about 85%.
Posted Thursday 5 Nov 2009 @ 11:52:39 am from IP # -
If you have a thick insulation you have essentially only conductive heat loss, not heat loss through radiation. This is because the outside of the insulation is already pretty cool. And colder surfaces emit much less radiation than warmer surfaces.
On the practical side: pool noodles (the ones with a hole in the middle) are probably the cheapest and most efficient insulation material you can get. Armaflex is with about $6 per meter as expensive as copper pipe. But you can buy a pool noodle of about 1.5 m length for just about $2 in a dollar store. It is thicker than Armaflex and it is UV resistant. It is also stiffer, which is a good thing as you can slit it along the length and it snaps easily around a 1/2" copper pipe.
Posted Thursday 5 Nov 2009 @ 12:32:29 pm from IP # -
dymonite69
MemberSun2stream is right. The effect won't be additive. However, I have seen foil lined foam lagging somewhere before. But if it gets dusty it will lose its effect anyway. I wonder how the pool noodle R value compares to the commercial stuff.
Posted Thursday 5 Nov 2009 @ 1:32:16 pm from IP # -
Greg
MemberIf only I were rich ... http://www.aerogel.com.au/index.php?page=spaceloft
What temperature can the pool noodle cope with ? Looking for something effective for the output from solar hot water panels.
Posted Wednesday 11 Nov 2009 @ 1:31:37 am from IP # -
The pool noodles are made of polyethylene (PE) which melts at about 120C. However PE gets soft a bit earlier. I had no problems with hot water systems. However when I was running steam at 100C through a copper pipe, the noodle around the pipe started to break up from the inside.
When I used a silicone rubber hose instead of a copper pipe in order to contain the steam, the pool noodle insulation did not suffer at all.
Posted Wednesday 11 Nov 2009 @ 9:42:58 am from IP # -
StephenG
MemberAnother pipework insulation is preformed fibreglass insulation. It comes with or without a foil face. It works well at high temperature. Not sure of the cost though.
http://www.forman.co.nz/upload/pdf_documents/ds_001_preformed_pipe_section.pdfPosted Tuesday 24 Nov 2009 @ 8:17:47 am from IP # -
TonyT
MemberFrom
http://www.engineeringtoolbox.com/copper-pipe-heat-loss-d_19.html
if the water inside a pipe is 38degC hotter (e.g. 58degC) than the surrounding air (e.g. 20degC), the chart shows that the heat that is lost from un-insulated 13mm (1/2 inch) diameter copper pipe is
32Watts per metre of length.
This heat loss is the result after the interplay between all 3 heat transfer mechanisms: conduction, convection and radiation.Can anyone confirm that for the same conditions the heat that is lost from un-insulated 13mm PLASTIC pipe is also about 30W/m ?
From
http://www.engineeringtoolbox.com/heat-loss-insulated-pipes-d_1151.html
if the water inside a 13mm pipe is 40degC hotter than the surrounding air,
then the heat-loss from a pipe enclosed in insulation that is 10mm thick is
17W/m.
CONDUCTION through the insulation accounts for most of the heat that is lost from an insulated pipe.Similarly, other charts show that the heat loss from 13mm pipe is 9.5W/m for 20mm of insulation,
8.2W/m for 25mm insulation and
7.2W/m for 30mm of insulation.Insulation 10mm thick reduces the heat loss by (32 - 17) = 15W/m.
Over 24hrs the heat saved by 10mm insulation is 24 x 15 = 360Watthours = 0.36kWh per metre per day.If our hydronic heating system operates for 24hrs/day and 200days/yr,
the heat saved by the insulation is 200 x 0.36 = 72kWh/m per year.If one kWh of heat comes from one kWh of electricity costing 20cent/kWh,
the saving is 72 x $0.20 = $14.40 per metre per year.If heat costs 5cent/kWh (e.g.from a heat pump using night tarrif electricity), the saving reduces to $3.60/m per year.
Tubes of foamed nitrile rubber insulation with 20mm Inside Diameter and with 12mm wall thickness can be bought for $2.20/m from Heatcraft in Adelaide on phone 08 8354 0100.
Alternatively, "Thermobreak" insulation includes an outside layer of aluminium foil and it is slit along its length.
It is made from foamed polyolefin material so it is lighter and stiffer than foamed nitrile rubber.
For 20mmID and 20mm wall the price is $4.10/m from Eastwood Insulation at phone 08 8244 8655.
For "Thermobreak" see:
http://www.sekisuipilon.com.au/pdf/4.9%20R%20value%20Tables%20-%20Thermobreak%20Tube.pdfFor foamed nitrile rubber insulation with a greater thickness of 20mm, the cost is $3.30/m and for heat costing 20cent/kWh the saving increases to (32 - 9.5) = 22.5W/m, a saving of $21.60/m per year.
On page 4 of the product specifications at
http://www.armaflex.com.au/www/armacell/ACwwwAttach.nsf/ansFiles/FRArmaflexAUS.pdf/$FILE/FRArmaflexAUS.pdf
the R value for a foamed nitrile rubber tube with 20mm ID and with 19mm wall is
0.86 + 0.13 = 0.99.
For this R value the calculated heat loss
U = 1/R = 1/0.99 = 1W/sqm per degC.For a one metre length of insulation with ID=20mm, the area that is perpendicular to the flow of heat is the surface of a cylinder with diameter 20mm and length 1 metre.
This area is Pi x 20 x 0.001 x 1 = 0.063sqm.For a one metre length of 20mmID insulation with R=0.99 and with a temperature difference of 40degC, the calculated heat loss
U = 1W/sqm x 0.063sqm x 40degC = 2.5W/mThis calculated value of 2.5W/m is much less than the value 9.5W/m that is read from the chart.
The charts may be drawn for pipes lagged with older insulating materials (? asbestos).
Modern foamed insulation materials are probably more efficient than the old lagging materials.Posted Tuesday 13 Mar 2012 @ 9:46:25 am from IP # -
ghostgum
MemberTonyT said:
Can anyone confirm that for the same conditions the heat that is lost from un-insulated 13mm PLASTIC pipe is also about 30W/m ?It's less. I did the calculation once based on the R value of PEX, and the result was that PEX pipe had the same insulating properties as copper pipe with the thinnest green insulation available. That is, it wasn't good enough. My PEX hydronics pipes were insulated with foam tubes, but the domestic hot water pipes unfortunately weren't. I have retrofitted insulation on the hot water pipe to the kitchen sink and I do notice the difference.
If our hydronic heating system operates for 24hrs/day and 200days/yr,
the heat saved by the insulation is 200 x 0.36 = 72kWh/m per year.As you stated, the foam insulation used on hydronic systems may be better than the chart on which this figure is based. Secondly, heat lost from the hydronic pipes may still be retained by the house. Some of the hydronic pipes under my house are between the underfloor insulation and the floor, so we gain most of that heat. Other pipes are below the insulation because they are running diagonal and are not between the floor joists.
On page 4 of the product specifications at
http://www.armaflex.com.au/www/armacell/ACwwwAttach.nsf/ansFiles/FRArmaflexAUS.pdf/$FILE/FRArmaflexAUS.pdf
the R value for a foamed nitrile rubber tube with 20mm ID and with 19mm wall is
0.86 + 0.13 = 0.99.
For this R value the calculated heat loss
U = 1/R = 1/0.99 = 1W/sqm per degC.This calculated value of 2.5W/m is much less than the value 9.5W/m that is read from the chart.
The charts may be drawn for pipes lagged with older insulating materials (? asbestos).
Modern foamed insulation materials are probably more efficient than the old lagging materials.I would also expect that modern foam insulation is better than older lagging materials.
Posted Tuesday 13 Mar 2012 @ 10:39:03 pm from IP # -
TonyT
MemberThanks Ghostgum
Please will you check my calculations:
For PolyButylene (PB) the thermal conductivity is 0.14W/m.degC
For foam insulation the thermal conductivity is about 0.03W/m.degC.
Nominal "18mm" PB pipe has a measured Outside Diameter of 16mm and a wall thickness of 1.7mm.
The thickness of foam insulation with the same thermal conductivity as 1.7mm of PB is
= 1.7 x 0.03/0.14 = 0.36mmCompared with a heat loss of 30W/m from non-insulated pipe and 17W/m for 10mm of insulation, I am guessing that adding 0.36mm of foam insulation would reduce the heat loss by less than ? one watt/m.
Posted Tuesday 13 Mar 2012 @ 11:24:36 pm from IP # -
peter69_56
MemberIf you go to a plumber supplies you should be able to pick up armourflex 3m lengths for about $3.50 (not solar armourflex)I retrofitted all my HW piping in the house even though it was plastic pipe already Made a big difference and cost me about $50 all up. Just split the insulation with a knife and slid it on.
Posted Thursday 15 Mar 2012 @ 7:06:49 pm from IP # -
TonyT
MemberThe (? German) Company Armacell (03) 8710-5999
is the distributor for two tubular, foamed nitrile rubber insulation products branded Armaflex and IndaflexArmaflex has been tested using Australian Standard ASTM C518.
Indaflex is made in Malaysia and it looks similar to Armaflex.
Indaflex has not been tested for compliance with Australian Standards.
In Adelaide both Tradelink and Reece sell Indaflex/Armaflex in 2m lengths at about
$2.20/m for 20mm bore with 12mm wall and at
$3.30/m for 20mm bore with a thicker, 19mm wall.Heatcraft 08 8354 0100 and Fitch 08 8346 5793 both sell Indaflex for similar prices.
Each of the Fire Retardant (FR) version, the High Temperature (HT) version and the Solar version of Armaflex are marketed for about double the price of Indaflex.
Black corrugated drainage pipe (un-slotted) can be used to protect the soft foam tube from damage by people, by rats or mice or by UltraViolet light.
A foam tube with ID=20mm and a 12mm wall fits inside drainage pipe with OD=65mm costing $1.60/m.
Larger drainage pipe with OD=100mm costing $3.20/m is needed to protect foam tube with ID=20mm and a thicker 20mm wall.Technical data for Armaflex from
http://www.armacell.com/WWW/armacell/INETArmacell.nsf/standard/0922D709141031BA8025772A0051AE77
lists
Thermal Conductivity =0.036W/mdegCThe R-value Table for Armaflex shows that
for tube with ID = 20mm and wall 12mm (Costing $2.20/m) the thermal Resistance
R=(0.53+0.13)=0.66For a 1m length, the heat loss
U = 1/R = 1/0.66 = 0.0952Watts per degCFor a temperature difference of 40degC
the heat loss is 40 x 0.0952 or
3.8Watts per metre lengthThis heat loss compares with the heat loss of 17W/m that can be read from the Chart drawn for 10mm-thick insulation at
http://www.ata.org.au/forums/topic/290#post-25320For thicker tube with ID=20mm and wall 20mm (Costing $3.30/m)
R=(0.86+0.13)=0.99
For a temperature difference of 40degC, the heat loss decreases to
2.5W/mIf the insulating tube includes an outside layer of reflective foil to reduce heat loss by radiation then R increases by 0.2
Compared with a tube with a 12mm wall, the tube with the thicker, 20mm wall costs an additional ($3.30/m - $2.20/m) = $1.10/m.
If a pipe with OD=20mm is heated for 24hrs/day and 200 days (6.5 months) per year, the heat energy that is saved by using a 20mm wall instead of a 12mm wall is
(3.8 - 2.5) = 1.3W/mThe annual saving per metre length is 1.3x24x200/1000 = 6.2kiloWatt-hours per year.
If heat energy costs 20cent/kWhr this energy saving is worth $1.24/m per yr.
For heat costing 5cent/kWh (e.g. from a heat pump using night tarrif) the saving reduces $0.41/m per year.
Sekisui Pilon manufacture insulating tubes made from a foamed polyolefin under the brand Thermobreak.
http://www.sekisuipilon.com.au/images/stories/pdfs/thermobreak-tube-insulation.pdfThermobreak tubes are pre-slit along their length and they have reflective foil attached on the outside.
Their foamed poly-olefin material is flexible but it is stiffer than foamed nitrile rubber.
Their foamed poly-olefin is about half the weight of foamed nitrile rubber.
The price for Seksui Pilon tube with ID=20mm and a 20mm wall is $4.10/m from Eastwood Insulation 08 8244 8655.Thermotec is another brand of pipe insulation.
Thermotec is made from foamed polyethylene.
It is made in Australia at Revesby NSW 2212 phone 02 9771 6400
http://www.thermotec.com.au/uploads/Thermotec%20Pipe4ppLR%202010.pdfIncluding a foil outer layer, the price of Thermotec with ID=20mm with 20mm wall is about $7.50/m
Posted Friday 16 Mar 2012 @ 2:35:34 am from IP # -
TonyT
MemberFor pipe insulation with ID=20mm,
the following Table may be useful to decide the optimum thickness of the wall:Question: Within a post, is it possible to align the columns in a Table ?
Wall Thickness: 12 12 20 20
Includes Reflective foil outer ?: No Yes No Yes
Product Brand: Indaflex Thermobreak Indaflex Thermobreak
Foamed Material: nitrile-rubber polyolefin nitrile-rubber polyolefin
Thermal Conductivity for Material only: 0.032 0.036 0.032 0.036
Thermal R value: 0.66 0.86 0.99 1.19
Heat Loss for Temp Difference=40degC in Watts per metre: 3.8 2.9 2.5 2.3
Cost $/m: 2.20 ??? 3.30 4.10
OD of protective drainage pipe in mm: 65 65 100 100
Cost of protective drainage pipe $/m: 1.63 1.63 2.82 2.82Posted Sunday 18 Mar 2012 @ 8:51:40 pm from IP # -
I would like to modify the heat loss formula a little.
So instead of 24 hours per day, most pipe insulation is only 'working' for say about 6 hours a day. These are the time slots when hot water is circulated from the solar collector or when a tap has been opened to take hot water. ( I regard the assumption of 6 hours as a very conservative approach) This will reduce the calculated heat loss above to about 1/4 of its initial value.
The cost saving is even lower as in the warm season usually more heat will be produced than required. So more or less insulation does not make any difference. Let's say boosting is only active in the three coldest months per year, resulting in 1/4 of the initial value.
The potential cost saving is even lower as most electrical boosting is done from cheep night tariffs of about 8 cents per hour resulting in 0.4 of its original value.
Multiplying all these factors up: 0.25*0.25*0.4 = 0.025 equal to 2.5%
Or in dollars: $1.24/m per yr become a saving of $0.031/m per yrThis result is consistent with my experience that I pay less than $5 for electrical boosting of the solar hot water system per year (Sydney area, 2 people). So there are not many savings to be gained by further improved pipe insulation.
Posted Sunday 18 Mar 2012 @ 10:49:17 pm from IP # -
TonyT
MemberGreetings s2s !
Agreed.
The optimum thickness of insulation depends upon the assumptions.
The calculations in my earlier post apply only for a (hydronic heating) system that has water heated by electricity and flowing for 24hrs/day and 200 days/yr.
PS
Google led me to your website.
I can see why you have sourced your own pipe-insulation from overseas !Posted Sunday 18 Mar 2012 @ 11:08:26 pm from IP # -
TonyT
Members2s
We are not in Alaska but our situation is unusual.
The 120 year old walls of the cottage have high thermal mass: they are built from rocks, mud and mortar, masonry that is 0.5m thick.
The walls take several days to warm up (or to cool down) so my goal in winter is to keep them warm 24hrs/day and 7 days/week.
As an experiment, in one room we ran a thermostat-controlled, oil-filled electric heater for 24hrs/day and 7days/week for about 6 weeks including the month of July.
The measured kWh of electricity showed that the average heat input was 600W.
From the Bureau of Meteorology, for Mt Lofty in the Adelaide Hills the daily mean maximum temperature ranges from 22.2degC in Feb down to 8.6 in July.
The mean minimum temperature ranges from 14degC in Feb down to 4.9 in July.
The temperature of the hot water supplied by the heat pump is max 60degC.
The calculation in the earlier post used an air temperature of 20degC and a temperature difference of (60 - 20) = 40degC in order to calculate the heat loss from the 16mm OD poly-butylene pipes that supply the hot water to and from the radiators.
The hydronic wall-mounted radiator panel in each room is designed to deliver a continuous output of 600W.
The Siddons heat pump HWS can provide maximum heat of 4,000Watts into the water.
We will start this winter by heating 2 rooms (each 600W) plus 2 towel rails (each 300W), a total of 1,800watts.
Provided that this is successful I will add additional wall-radiators.
Posted Monday 19 Mar 2012 @ 1:28:34 am from IP # -
Sorry, I am moving away from the subject of the thread, but I agree, using a heat pump for hydronic space heating is a good idea (as long as the noise level is no issue).
However, even with a high thermal mass, there is no place in Australia (with the exception of our slice of Antarctica and some Southern islands)where you have to heat for 200 days per year.
It is also a misconception that keeping the temperature 100% flat is saving energy, even with high thermal mass. You still save more energy if you allow the temperature to drop a little while everybody is sleeping (and raising it again maybe with a timer, so it's cosy when you're up)
Posted Monday 19 Mar 2012 @ 2:08:01 am from IP # -
TonyT
Members2s
By using the system over this winter we will learn the annual number of heating days that we need and for how many hours per day the system needs to operate.
We will certainly try setting different temperatures for the night and the day.
Posted Monday 19 Mar 2012 @ 2:48:05 am from IP # -
peter69_56
MemberForgetting efficiency, it provides better sleeping conditions if the inside temperature is allowed to fall during the night, and then raised when awake. To have the temperature at a constant setting is too hot for normal sleep rhythm.
Posted Tuesday 20 Mar 2012 @ 2:03:53 am from IP # -
Rocket Ros
MemberHi Matt, I have a solar hot water system and the pipe insulation that was used is the Aeroflex HT solar pipe insulation rated at 175 degrees and UV stabilised.It was put up 18 months ago and still looks good as new. The website that has all info can be found at http://www.australiansunenergy.com.au/pipe.html. I beleive they have the full range of pipe insulation.
Posted Saturday 24 Mar 2012 @ 8:37:43 am from IP #
