What are a set of ps360q worth??

[Charles]

What are your finger arrangements? Do you have fingers at the very end? Do you have the opening flaps in place?

 

[George_Mills]

Hi Nick

the PS 360 is smaller oven at 135,000 BTU the 3270 is a larger oven 111.2 in as compared to 90 in for the PS 360 and is a 190,000 BTU system.

It is a very difficult to compare the two systems without knowing the negative BTU loads imposed on the two systems.

If the Middleby PS-360 in question are rebuilds and if the rebuild was properly done they would have been equipped with high efficiency burners and modulating gas valves which were not available at the time most all of those ovens were produced. Middleby recently resumed production of the 360 and possibly includes those improvements although thy have not mentioned that in there advertising.

Note also there is an adjustment on the gas burners of both makes of ovens that sets the amount of oxygen mixed with the gas. If that device is not adjusted properly the efficiency of the burner will be reduced and much more gas used.

Again addressing heat out the ends of the ovens. More heat is being generated in the larger oven and the space allocated for the heat to escape is the same for booth ovens there is usually more heat escaping out the ends on higher BTU ovens. Also he PS 360 Ovens Have an exhaust pipe, (flue Pipe) and that exhausts a tremendous amount of heat that does not have to exit via the ends.

The reason for the flue pipe on older ovens, it was required by regulation because the older burners only burned about 80% of the gas. The newer ovens have burners that use 98% of the gas and therefore do not need flue pipes. the heat that used to be lost out the flue pipes is now used for baking but adds to the heat discharged out the ends.

there is a ventilation system for conveyor ovens that captures the heat discharged from the oven ends and exhausts it and only takes 720 to 880 CFM of air out of the building (depend on ovens being used) so no make up air is required, (assuming proper A/C). That’s not to say that workers near the ovens are not warm. There is radiant heat coming off cooking devices. That heat is like the heat coming from the sun, it passes through millions of miles of space and does not warm that space but when it hits something or someone, It heats them. That type heat cannot be removed by ventilation.

The shops using the above mentioned system lose a lot less A/C through the Hood.

George Mills

 

[George_Mills]

Hi guys
There follows some calculations on gas price to run ovens.
The following assumes the ovens are operated at full power all the time.

one cubic foot of gas provides 1020 BTU of heat per hour
For instance the XLT- 3270 single deck has a maximum consumption of 190,000 BTU per hour Divided by 1020 that equals 186.27 cubic ft of gas burned per hour at maximum heat production.
186.27 cubic ft Times 12 hours operation Equals 2235.24 or 2.24- thousand cubic feet of gas per day Times say $12.00 per 1000 cubic feet of gas equals $26.00 per day cost of operation times 365 days equals $9,811.20 per year operating cost if running atfull load.

The figures for the cost per 1000 cubic feet of gas can very from place to place and the days and hours of operation can change . but the formula remains the same. So plug in your ovens BTU, the cost of gas per 1000 cubic feet in your area and the hours and days you operate and you should have the maximum operating cost per oven.

If your operating cost is more than your answer check for other gas consuming units in your shop. If you have a make up air unit it is using gas to heat the inbound air when the whether is cool. You may have a gas hot water heater.If so a hot water leak can cause higher than normal costs. You probably have a gas furnace that could burn some gas despite the heat of ovens possibly during the night when the ovens are shut down.

The above is the way I calculate gas usage and cost, if someone has a more accurate system Or if some gas expert see a flaw in my calculations I would be happy to hear from them.

George Mills

 

[Charles]

George, you cannot just compare BTUs for energy cost though, right? Because one that is at 190K BTU might actually use less than another at 160K BTU to achieve the same temp if they have modulating valves. In essence, the 190K may come on for a shorter time than the 160K model.

So do these ovens go through some standardized testing where they maintain a certain temperature for a certain time and the actual gas usage is measured?

 

[George_Mills]

quote=“Dewar’s Pizza Bakery”]George, you cannot just compare BTUs for energy cost though, right?

Gm: correct the difficulty in making comparisons is that the only way to make a comparison would be to have the two units side by side and run the exact same products through them at the same temperature for the same amount of time and have sensitive gauges attached to determine the amount of gas used by each.

quote:Because one that is at 190 K BTU might actually use less than another at 160 K BTU to achieve the same temp if they have modulating valves. In essence, the 190 K may come on for a shorter time than the 160 K model.

GM: A better way to explain the value of the modulating gas valve is to compare two, exactly the same, automobiles run over a couple hundred miles. one automobile ( representing the modulating gas valve) is driven the entire course at a steady 60 mph only depressing the gas pedal only to climb hills at the steady speed.

The other auto ( representing no modulating gas valve) leaves the starting line with the gas pedal floored up to 60 mph and when that speed is hit the foot is completely off the gas pedal and the speed slows to forty then the gas pedal is floored again up to 60 and that is repeated over the entire course. the net result is the accelerating then slowing vehicle will use more fuel then the unit operated at a steady speed.

[/quote: So do these ovens go through some standardized testing where they maintain a certain temperature for a certain time and the actual gas usage is measured?

GM:No that is not done any more than every automobile off the production line is tested for gas mileage. The ovens are run for several hours and adjustment made for maximum gas burner efficiency and that all components are operating correctly. Gas consumption of each oven is not determined.

In another post Wizzle Wassell asks about the adjustable panels that reduce the height of the conveyor ovens opening at the entrance and Exit.

GM: Yes they do help to reduce the out flow of air but I don’t think it is a major reduction.

George Mills

 

[Wizzle_Wassell]

paul7979:

Wizzle, are you using 3255’s or 3270’s?

I’m on 3255’s

 

[paul7979]

Wizzle Wassell Posted:

I’m on 3255’s

That may be the difference. The 3270’s have a blower motor on each end of the oven which might add to the amount of heat that blows out each end.