Thursday, May 23, 2013

Vacuum Panels versus foam insulation

I have seen too many failures over the years to even consider them. Cruisers spent a fortune rebuilding their galleys only to have to start all over again. Once you can put a sailboat in orbit maybe I might consider them. End of story.

Sunday, May 12, 2013

Building a Real Box for the Unreal Heat in Sea of Cortez and other tropical destinations

As I mentioned in previous posts it's all about insulation, insulation, insulation. That's what stops the heat leaking into the box and reduces the amount of time the refrigeration system has to run. Many production boats have totally inadequate boxes....even some new ones. So a production boat ice box may have you running the engine to keep up with electrical usage, hauling ice, looking for a marina to plug into and basically making your enjoyable cruise into a living nightmare. I know of several couples who have split up or quit cruising because of a simple comfort issue.

The following photos show a box that will yield 8.5 cubic feet of space, of this about 1.5 cubic foot will be a freezer maintained at around 10 deg. F and the rest a fridge of 7.0 cubic foot maintained at 34 to 38 deg. F. To put this in real terms, the freezer could easily hold over 30 lbs of frozen meat, fish or veg. properly packed and pre-frozen. If the fridge area was packed to its gills it would hold over 328 regular cans of beer, or over 14 cases. However there would be no room left for food..lol. The amount of poured foam was about 21 cubic feet.


The first step is to gut the original factory box, 2 to 3 inches of 30 year foam in this case just would not work in tropical conditions



The holes were for drawers that have been relocated. To the left of this shot you can see the original skimpy box lids...not enough insulation.





The next step is to make a new box liner, this is a two part process, first you have to  make a wooden "plug" from which you can make a fiberglass mold which will be the box liner. Here it is cut in two so as the liner could be popped off of it. You can see the transparent PVA film which is a mold release agent.




AND here is the new box liner dropped into place




Next it needs to be correctly positioned in the enclosure so we will have 5 inches of foam around it and over a foot on the hull side.


You will see the plug as been dropped into the liner and wooden beams screwed into place. This is needed as the expanding foam creates a huge pressure and would buckle the box and force bulkheads out of shape. So the strong backs also need to be fitted on the outside of the box too.



Now to make sure of damage control. The expanding foam produces noxious gases and sticks like shit to a blanket.



Here is the foam. It's two part, mix up a two quart batch, stir for 20 seconds with a mix master fitted with a custom spray guard and pour rapidly.......don't waste a SECOND o.k..

Here is a link to the foam used, a good time to learn a little Spanish!


You will notice the foam gives of heat, so after the first 3 pours the job stopped for 20 minutes to let things cool down. If not the second level of pour will go off too quickly and make large gas bubbles instead of dense insulation.  Keep pouring foam until the void is full. Use the custom cardboard sheets to make sure it goes where you want it to go!

Note the can of Tecate beer, it is essential in the correct application of the foam!



Now the box is fully foamed all the wood is removed and excess foam trimmed off ready for the fibreglass moulded and foam cast box top to be fibre glassed to the liner. 


And the wood is gone!

It still needs detailing to accept the box top

This is the box top prior to detailing,
And the underside, all foamed and sealed with glass fibre
 It took two steps to make this, first you make the wooden plug, then you make the molding from the plug and then the same process for the box lids. As you can see here the wooden plug was broken off the molding. Each and every boat is different so it is all labour intensive custom work. Below is the plug for the top..

  The lids too are filled with foam and need to be made from a custom mold too, here it is being faired out by hand.

And the underside of the lid mold

 A tube passes through the box bottom into the bilge area. This is fully glassed into the liner and extends 9" above the box bottom, so no chance of water getting into the foam.Through this tube the pressure and suction tubes of the Mexicolder system along with thermostat wires are run. The tube is then stuffed with plastic bags and sealed on the top with aluminum duct tape and silicon caulk. Don't use polyeurethane sealants inside the box , they gas off and taint the food for weeks.
Here you can see there is 10" of foam under the box

At last the box top is fitted

No more skimpy lids, these will do the job....no sweat, pun intended!


There are sliding bases to make easy access to the bottom of the box


The evaporator will be fixed here, the under panel helps support the weight but can slide out for access and easy cleaning


The finished job


 A carpenter will secure the original fiddle rails. Foam tape rubber seals makes the whole thing air tight. The box top is joined to the box with a thick catalysed resin paste making the entire structure "monocoque". Any holes drilled into the box liner to attach the evaporator or thermostat are caulked to keep the water tight integrity of the liner. Unless the customer specifically requires a drain we don't install one. They tend to get smelly in time. Instead a hand type pump can be used to suck water from the box and any bits of food or spilled liquids. The pump is then flushed out and left in the sun to dry.....no more smelly bilged boats. I swear I can smell a boat that has an ice box drain from several boats away.

The compressor is mounted behind the aluminium grill

Note all the tubing is fully brazed up with silver copper phoshorous rod, no chance of leaks


The condenser draws air from the cabin and is sealed to the grill, warm air escapes from the louvred teak door and keeps stuff nice and dry in the locker too!


Sunday, May 5, 2013

A great crusty and high density french bread recipe


This recipe makes 2 large loaves , we make the dough and bake one loaf and freeze the other half of the dough ready for a second bake.
·       
6 cups all-purpose flour
·         
2 1/2 (.25 ounce) packagesactive dry yeast
·         
1 1/2 teaspoons salt
·         
2 cups warm water (110 degrees F/45 degrees C.

1 tablespoon cornmeal or you can use white flour
·      
1 egg white
·         
1 tablespoon water

Directions
1.   In a large bowl, combine 2 cups flour, yeast and salt. Stir in 2 cups warm water, and mix until well blended. Using a wooden spoon, stir in as much of the remaining flour as you can.
2.   On a lightly floured surface, knead in enough flour to make a stiff dough that is smooth and elastic. Knead for about 8 to 10 minutes total. Shape into a ball. Place dough in a greased bowl, and turn once. Cover, and let rise in a warm place until doubled.
3.   Punch dough down, and divide in half. Turn out onto a lightly floured surface. Cover, and let rest for 10 minutes. Roll each half into large rectangle. Roll up, starting from a long ide. Moisten edge with water and seal. Taper ends.
4.   Grease a large baking sheet. Sprinkle with cornmeal or plain flour . Place loaves, seam side down, on the prepared baking sheet. Lightly beat the egg white with 1 tablespoon of water, and brush on. Cover with a damp cloth. Let rise until nearly doubled, 35 to 40 minutes.
5.   With a very sharp knife, make 3 or 4 diagonal cuts about 1/4 inch deep across top of each loaf. Bake in a preheated 375 degrees F (190 degrees C) oven or on the 2/3rds BBQ with a heat deflector and place the baking sheet on a cake rack to get indirect heat for 20 minutes. Brush again with egg white mixture. Bake for an additional 15 to 20 minutes, or until bread tests done. If necessary, cover loosely with foil to prevent over browning. Remove from baking sheet, and cool on a wire rack.

·         PREP25 mins
·         COOK40 mins

Banana Bread

I'm sure there are lots of recipes out there. This has worked for us. Enjoy


TORTUE Banana Bread Recipe
·         Prep time: 5 minutes
·         Cook time: 1 hour
INGREDIENTS
·         3 or 4 ripe bananas, smashed they were 3 large bananas or 4 smaller
·         1/3 cup melted butter
·         3/4 cup sugar  or less
·         1 egg, beaten
·         1 teaspoon vanilla
·         1 teaspoon baking soda
·         Pinch of salt
·         1 1/2 cups of all-purpose flour
·          1 shot rum
·         Half cup almonds or any kind of nut  chopped coarse
·         1 tsp cinnamon
·         I cooked on the bbq  WEBER Q120  on 2/3rds heat on cake rack above heat deflector 1 hour….perfect
METHOD
No need for a mixer for this recipe. Preheat the oven to 350°F (175°C) or the BBQ on 2/3RDS heat.  With a wooden spoon, mix butter into the mashed bananas in a large mixing bowl. Mix in the sugar, egg, cinnamon, rum and vanilla. Sprinkle the baking soda and salt over the mixture and mix in. Add the flour, mix and last the nuts. Pour mixture into a buttered 4x8 inch loaf pan. Bake for 1 hour. Cool on a rack. Remove from pan and slice to serve.
Yield: Makes one loaf.

Saturday, May 4, 2013

The good life and getting better mileage out of your vegetables

During the summer months we take off to the Sea of Cortez with a freezer full of rock solid meat and a fridge full of cheeses, cold cuts and fresh veg The bilges are full of dried goods and all the canned stuff we need. Once we start catching fish our diet becomes more healthy.  We bake bread twice a week and make home made pizza on the BBQ. When making the dough we divide it in 3 for the pizzas and in 2 for the bread. We then freeze what we don't use immediately. That way we can take the frozen dough out the night before and it will have risen again ready for our bake the next day. Our over ripe bananas get made into banana bread, this goes onto the BBQ after a bread or pizza bake and thus saves on propane use.

About the only cost we have besides keeping the beer locker full is fresh fruit and fresh vegetables.
Every Sunday there is a farmers produce market in Loreto and I'm sure in other places too. Initially we would only get a few days out of the fresh stuff until we started washing EVERYTHING in a solution made of colloidal silver drops and water. You can find the stuff at any supermarket in the Fruit and Veg. area. As it kills all the bacteria on the surface of the produce it will help stop you getting Moctezumas Revenge too!





We found this at SAMS club..Bakers and Chefs brand, it comes in 1/2 litre bottles too
.

After washing in the solution we air dry everything in a breezy shaded area before bagging it in the Evert Green bags and then refrigerate all but onions and potatoes which we keep in net bags either side of the galley. Now we can go close to 3 weeks between vegetable purchasing!

Box Seals

Down in Mexico we can at times have problems finding stuff. In most cases when making sure the box has a good seal on the opening we use a foam rubber tape which is readily available and you get good service from it, perhaps you need to replace it every few years? Some of the newer boats such as Hunter have a more elaborate seal. It seems that after several years they harden up, maybe because of ozone or perhaps due to a cleaner used.

Here's a link to where you can find what you need and bring it down with you. Thanks to Colin on Pacific Raven who researched it.

http://www.cooler-gaskets.com/

Friday, May 3, 2013

OK I know I've bored you with too much tech talk: Here follows some Brit Humour

http://www.mez.co.uk/lucas.html


Enjoy

Cabo San Lucas will never have that allure when you realize it was named after Joe Lucas

a.k.a The Prince of Darkness

RETRO FITTING KEEL COOLED SYSTEMS

Over the years Mexicolder has retro fitted many systems that use through hull keel coolers.
These systems use the exactly the same compressor as does the Mexicolder. Even water cooled systems are less efficient as the energy used to power the pump takes more from the system than it gives....An ever increasing entropy.

The disavantage is that when you are hauled for bottom work you lose all your refrigeration.


The  alarming defect in the system is that in tropical waters the keel cooling plate and or associated through hull fitting is too small to efficiently remove heat from the hot condensing refrigerant gas.

This is evidenced by simply measuring the temperature of the liquid refrigerant after it exits the condenser/keel cooler, this enthalpy curve allows us to determine ho much energy is lost due to the FACT that small through hull condensers offered on several off the shelf systems are very inefficient in tropical waters.

 http://www2.dupont.com/Refrigerants/en_US/assets/downloads/h39917_hfc134a_pressure_enthalpy_eng.pdf


If the liquid refigerant temperature is significantly higher than ambient air or water temperature then you have a huge inefficiency built into the system as when the above ambient liquid refrigerant vapourizes  it is heavily taxed by reducing it's temperature using the  "latent heat of vapourization of HFC 134a", which was supposedly going to be used to take heat from the evaporator. If this is too technical for you, just trust me it follows the second law of thermodynamics.

http://www.grc.nasa.gov/WWW/k-12/airplane/thermo2.html

http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookener1.html

The  fact....is that in 20 plus years of using the Danfoss BD series compressors these are the only failures I have seen. Here is an example

http://www.sailblogs.com/member/followyoufollowme/?xjMsgID=76920

Read the third blog entry down from the top  Refrigeration 101 and 102 



The retrofit involves installing a double air condenser within the system.

My client jokingly failed to see how this would use less energy than the static keel cooler as the fans pull 0.34 amps. Let's say this guy is no dummy and is well versed in engineering. A year later I returned to retrofit his second system as he had spent a year monitoring the retro system and this was the icing on the cake (pun intended). It used considerably less energy.

I will try and get the results directly from him to prove this fact so keep an eye on this space.

Well here it is from the horses mouth..so to speak:


Hi Mike- I read you blog and found much useful information, good job. Regarding the retrofit you did on my boat, Sandpiper, an island packet 420. You may recall when I purchased the boat it had a stock refrigerator/freezer with two separate compressors using keel coolers. In southern California, my home waters, these operated well because the water temperature is quite low, typically between 55 and 65 deg F. However when I took the boat to Mexico the time to cool down became noticeably longer. The first problems occurred with the freezer when the copper tubing connection to the keel cooler corroded through with resulting loss of coolant. Because these connections to the keel coolers are necessarily located in the bilge areas they are prone to salt water immersion and can easily corrode. The keel cooler manufacturer did not offer any solution other than to replace the cooler plate. The quoted cost to haul the boat and replace the keel cooler plate was around $5,000. Lucky for me your solution, to replace all seals and fittings with a fully welded system and to use a large volume Mexicolder fan instead of keel cooling was only a small fraction of the cost compared to replacing the keel cooler. In the two years since this was done I have had only good experiences with the air cooled system. Running side by side with the refrigerator system (still keel cooled) it was easy to see the differences. The freezer ran for half the time of the refrigerator and used approximately 30 A-hr per day. In the summer heat, the outside water often reached into the 80-90 deg range and the refrigerator compressor ran almost continuously. Based upon this experience I elected to have the refrigerator system also converted to air-cooling and since then the total drain for both systems is approximately 60 A-hr per day. As a bonus I no longer worry about corrosion of cooper tubing in the bilges. 
Best regards,
Ed Staples
S/V Sandpiper


It would seem that some smart advertising and business types have sold cruising sailors down the road on these systems? If that is the case at this miniscule end of "heat transfer pumps" It makes me shiver to think as to where big industry is and how much precious energy is being wasted on this planet?

I rest my case

A video link that will show you how regular simple maintenance will save lots of precious solar amp hours

Although the system you will see when you view the video on this link is many times bigger than your tiny boat unit it operates ON THE EXACTLY THE SAME PRINCIPAL as a Mexicolder system

So occasionally vacuum any dust or dirt off the condenser fins. Defrost on a regular basis and and make sure the box seals are in good condition. You'll get the same benefits shown on the video. The energy savings you'll enjoy will be less amp hour usage

As the Mexicolder is a hermetic system ( ie it is fully welded and there are no mechanical connections seals or motor alignment issues) this is all the maintenance needed. The other failure and maintainance points do not apply, they were engineered out of the loop! (pun intended)

Enjoy,

http://www.ecacool.com/en/videos/video-animation-starcare-industrial-refrigeration-maintenance-industrial-refrigeration-commercial-refrigeration-video.html

Stuck somewhere with a problem no one seems to be able to fix?


WHAT'S THE PROBLEM MATE?

We offer on line consulting. Search for MexiColder on Skype  or send me a mail at mexicolder@hotmail.com and I am sure I can help you get stuff working in many cases.

I am a Marine Engineer, not a technician with a little basic knowledge. I have 36 years SOLID experience in the Marine Industry. I have overseen the construction of Yachts and Megga Yachts, sailed them, delivered them, and have professional qualifications to back all this up.

So you may ask what I'm doing building energy efficient fridges?

 I enjoy it!

 On a big steam plant you maybe dealing with 50,000 horse power and these little fridges 1/16th of a horsepower. Not much room for error, but it all works on the same heat laws and principles of thermodynamics.

 I guess it's akin to making jewelry versus building power stations?


A new box

The galley was fully gutted on this C&C 38. The insulation was only 2 inches thick and it was wet. There was a huge void between the hull and the box liner. Now it's all foam and monocoque with the hull. Another beautiful job that will give many years  of use and YES it's easy to keep clean




Thursday, May 2, 2013

Spare parts for ANY system

We have a huge selection of spare parts for almost ANY system and can ship to ANY Mexican Marina, Business or home address, you just need some one to sign for the package.

 Tell us what you want, give us a full description, include the part number and the type of system it is going into.


We have it all in Mexico already saving you the cost and hassle of sourcing it north of the border and going through the typical customs nightmare!


Pictured is a Danfoss BD35 compressor complete with mounts, the 101N220 control module, a thermostat, fan and filter drier.

  Just email us at mexicolder@hotmail.com and we'll have that part to you quicker than a Mexican maƱana.

Unsolicited email


  • Power Test‏

Pacific Raven Colin and Margey (colin.harris1950@gmail.com)
Attachment
4/16/2013

Documents
To: Mike Wilson
MEXICOLDER REFRIGERATION RESULTS
Data collected on April 15th, in Mazatlan, Mexico, using a Xantrax Link 1000 Digital display, aboard Sailing Vessel “Pacific Raven”, Hunter model 40.5. Mexicolder evaporator installed in the freezer box, wall between freezer box and refrigerator box removed to allow cold air to circulate throughout. Other than the removal of the separating wall, the units are stock Hunter, 4” foam covered with a molded fibreglass surface. Note that gaskets on the sealing doors are due for replacement and are definitely leaking due to hardening. Upon replacement these recorded results should improve.
Day time: Recorded during the warmest part of the day, 1100-1600 Amp hours used during the 5 hours = 6.0 Average consumption during the period = 1.2 Amp hours per hour, or 15 Watt hours per hour Day-time average of 30 Amp hours per 24 hour day, or 360 Watt hours per 24 hour day Combined average is estimated at 27 Amp hours per 24 hour day, or 310 Watt hours per day
Night time:
Recording time 2200-
0800 April 16th Amp hours used during the 10 hours = 10.0 Average consumption during the period = 0.9 Amp hours per hour, or 11 Watt hours per hoMEXICOLDER REFRIGERATION RESULTS
Data collected on April 15th, in Mazatlan, Mexico, using a Xantrax Link 1000 Digital display, aboard Sailing Vessel “Pacific Raven”, Hunter model 40.5. Mexicolder evaporator installed in the freezer box, wall between freezer box and refrigerator box removed to allow cold air to circulate throughout. Other than the removal of the separating wall, the units are stock Hunter, 4” foam covered with a molded fibreglass surface. Note that gaskets on the sealing doors are due for replacement and are definitely leaking due to hardening. Upon replacement these recorded results should improve.
Day time: Recorded during the warmest part of the day, 1100-1600 Amp hours used during the 5 hours = 6.0 Average consumption during the period = 1.2 Amp hours per hour, or 15 Watt hours per hour Day-time average of 30 Amp hours per 24 hour day, or 360 Watt hours per 24 hour day Combined average is estimated at 27 Amp hours per 24 hour day, or 310 Watt hours per day
Night time:
Recording time 2200-
0800 April 16th Amp hours used during the 10 hours = 10.0 Average consumption during the period = 0.9 Amp hours per hour, or 11 Watt hours 
Outlook Active View
MEXICOLDER REFRIGERATION RESULTS
Data collected on April 15th, in Mazatlan, Mexico, using a Xantrax Link 1000 Digital display, aboard Sailing Vessel “Pacific Raven”, Hunter model 40.5. Mexicolder evaporator installed in the freezer box, wall between freezer box and refrigerator box removed to allow cold air to circulate throughout. Other than the removal of the separating wall, the units are stock Hunter, 4” foam covered with a molded fibreglass surface. Note that gaskets on the sealing doors are due for replacement and are definitely leaking due to hardening. Upon replacement these recorded results should improve.
Day time: Recorded during the warmest part of the day, 1100-1600 Amp hours used during the 5 hours = 6.0 Average consumption during the period = 1.2 Amp hours per hour, or 15 Watt hours per hour Day-time average of 30 Amp hours per 24 hour day, or 360 Watt hours per 24 hour day Combined average is estimated at 27 Amp hours per 24 hour day, or 310 Watt hours per day

Hi Mike - the system appears to be working very well. Even though we are cooling a much larger area than before, the unit is running much less. I've attached some numbers that you may be interested in. Once the gaskets are replaced and also with the freezer boxes full of cold food I figure the numbers might even get a little better. The Nova Kool that was removed was using something in the order of 60 Amp hours per day, so the Mexicolder is consuming less than half. If this performance proves out during our cruising next winter we will be delighted. Thanks Mike

I'm heading back to Canada tomorrow, hope you have a good trip to the Sea, see you in October.

Kind words from Fresco Don May


  • Testimonial‏

Fresco Don (Frescomexico@aol.com)
3/11/2013


To: mexicolder@hotmail.com
Hi Mike,

Just by way of recommendation for Mexicolder refrigeration systems. I have been servicing boat refrigeration systems in Puerto Vallarta since 1995. Many boats, on their way to points south, pass through both Mazatlan and Puerto Vallarta. In all these years, I have never had to service a single Mexicolder installation. If all systems were as good as yours, I would starve to death.
Regards,
Don May
Fresco Marine
Refrigeration Service