Heard that in my area they derate the natural gas so it works better in standard appliances. Anyone heard of this?
Hi there, so I'm working on some chiller calculations in my company. Basically, one of the Energy Management Opportunities (EMO) I have found after an energy audit was "Replacing the Chiller at the end of life-cycle"
Here are some of the existing data I have gathered:
Air Cooled Chiller:
- Cooling Capacity (kW): 178
- Rated Power (kW): 52.4
- Brand: Clint
- Compressor Type: Hermetic
- Type of Drive: No information
- Year Manufactured: 2013
Note: Chiller was manufactured in 2013 and has a life expectancy of 15 years so I'm gonna recommend them to replace the chiller in year 2028
Here are my calculations so far:
Chiller COP = Cooling Capacity / Rated Power = 178 / 52.4 = 3.40
Calculated COP at 2013: = 3.40
Calculated EER at 2013 = 3.412 * (Calculated COP at 2013) = 3.412 * 3.40 = 11.59 kJ/kW-hr
Existing EER at 2028 = EER at 2013 * (1 - %COP Derating every year)^(Number of years)
Number of year = Year 2028 - Manufactured Year = 2028 - 2013 = 15 years
For %COP Derating every year, I assumed it to be 2% (Just an assumption)
Existing EER at 2028 = 11.59*(1-0.02)^(15) = 8.56 kJ/kW-hr
Existing COP at 2028 = Existing EER at 2028 / 3.412 = 8.56 / 3.412 = 2.51
Recommended Minimum Efficient Chiller COP for Air Cooled Chiller with a size category of less than 150 Tons = 2.80 (Reference is ASHRAE standard 90.1)
So, my boss recommends that I use the %COP Derating every year to be 1%. However, if I do that my EER at 2028 would be 9.97 kJ/kW-hr, resulting to 2.92 chiller COP. The chiller would still be applicable to work since it is still above the minimum efficient chiller COP of 2.80. We can't replace the chiller if its like that.
Should, I use 2% or listen to my boss and use his value of 1% ?
Thanks!
So my def system started acting up last night saying the tank was empty and needed to be filled. I knew this wasn't the case and went to a truck stop nearby to fill it up. Only took 8 gal. This morning my truck is in all out scr engine derate 25% mode. Don't know whats happening so I'll be taking it to an International dealer this morning instead of picking up my load. Life is GREAT! Keep you guys posted.
I moved over from flying the PMDG 777 for a long time to now trying out the Zibo 737, but I’ve never actually calculated a good assumed air temp, or I’ve always just taken a quick guess. Would TOPCAT calculate this? If so, are there any free alternatives (like how simbrief is a good alternative to PFPX)?
Hi all,
I'm a homeowner trying to understand my future solar install as much as possible.
I'm going to be installing solar while at the same time making some changes to the service at my home to power a new detached shop. My plan is to upgrade my 200a service to 400a. The house already has a 200a panel and the shop will get a new 200a panel.
My thought was to put a new load center between the house and the meter/load center combo, as a place to connect the solar inverters, as well as a future connection location for backup batteries. This would be a 400a load center being fed by a 200a breaker from the meter/load center combo.
My solar designer is recommending a line side tap to connect the inverters into the system, as it's "easier" and they don't need to worry about de-rating for NEC code.
My question is: wouldn't a 400a main lug load center, fed by a 200a breaker be "de-rated" enough to handle the load of two 60a input breakers from the solar inverters, a 200a branch breaker that will feed my house's current main panel (to have the ground debonded to make it a sub panel) and three future 30a breakers for PowerWalls (or similar).
I'll likely have 2x SolarEdge 11.4 kw inverters.
Here is a visio diagram that I've created with my proposed design. Again, the solar designer is recommending a line side tap instead.
Diagram: https://imgur.com/CEBHkOZ
Thanks everyone!
***quick addition: As the solar inverters I'm getting are grid tied, they require power to be coming from upstream to generate electricity. As such, if I do backup batteries in the future, the inverters would need to be downstream of the Powerwall gateway (or automatic transfer switch) to actually be used during an outage from my power company. Wouldn't this alone negate the possibility of using a line side tap?
Filled up at the fuel station and pulled away only to be met with no power. Dumb luck had me less than one mile from the Volvo truck dealership so I limped there and bought a Davco and spin on fuel filter. Changed both out and the engine fault was still on. Still in de-rate!
Called my road side guy and he read the code with his laptop. Def heater malfunction. Fuck man. A def heater problem de-rates the truck! The code was reset and it has not come back up again but I am scared to take a load because of it.
I'm hoping it is just a Volvo gremlin. Any work arounds if this happens on the road?
Looking at ASC's regs for MOVs, the scoring formula for 2020 is:
S = (D / E) x C x T x P
where T is the Target Speed Derate
Per section 13.2.D of the regs, if a team's average speed is >= 35 mph, then T = 1.
If the average speed is less than 35 mph, then T = 0.4(35 - v)
So, if a team's average speed was 25 mph, then would T = 0.4(35 - 25) = 4? Obviously this can't be true since that would increase the team's score. Am I missing something here?
How did you guys calculate the assumed temp and derate for the 757? I got the CS 757 and the to me the manual for takeoff performance isn't very helpful. Do you just guesstimate?
I drive a 2013 Pete 337 rollback and while in tow, two yellow warnings came on: regen with a ! through it and the service engine ( check engine light with wrench through it). Also the little “water in DEF” light came on in my DEF gauge not long after. The truck seems to be running fine just not pulling as well as normal. The diagnostic says engine derate.
I am in south Texas and it has been pouring rain if that helps. I have tried to force a regen and it won’t do it.
Is it ok to keep driving the rest of the weekend? Or should I shut it down?
I would appreciate any advice. Thanks y’all! Be safe out there!
I'm going to assume reputable suppliers for all parts (i.e., not random eBay suppliers). I'm aware of the need to derate based on capacitance due to DC bias, but what's not clear to me is whether I need to give significant additional headroom for the breakdown voltage in some cases. TDK suggests this is not necessary but that doesn't seem to be the consensus in other fora (including this one).
For example, is a 16V cap adequate on a nominal 12v rail? How about 6.3v on a 5v rail? What about a 50V cap on 48V?
Can anyone suggest any reading material on practical engineering concerns like this (versus the theory aspects)?
I often hear driver's complaining over the radio that they are "getting a lot of derates." I understand that a derate is the electrical or perhaps total power package not producing full power for one reason or another. What are some reasons a driver might encounter derates during the race?
A diesel car is required to derate if the DEF tank runs dry or if there is some sort of particulate filter issue. Why aren't gasoline engines required to derate if a catalytic converter fails? Is it simply because diesel emissions are more harmful to the environment than gasoline emissions?
Hello everyone. I work for a Chicago area trucking company and have some questions. We have several dozen 2016 Petes and Kenworths in our fleet. For some reason the vast majority of these trucks derate at least once a month. I'm confused why this would happen. Is this a common thing amongst these trucks? I feel like my company is plagued by this. What would be a major reason for this to keep happening continually?
any help is appreciated. Thank you.
Arma Senton TX: Spektrum SLT3 Motor: Spektrum 85A brushless ESC: Spektrum firma smart series Battery: NiMH 7-cell
Just upgraded the motor and ESC, calibrated the remote. When driving I have 100% throttle for a seconds then it derates to maybe 50%. I've tried resetting the ESC, recalibration, battery swaps, with no change. It always starts out 100% then automatically derates. Any help is appreciated.
I've used topcat for years now for thrust derates (double derates) for the pmdg b738 and its always within a few tenths of a % N1 between what topcat says and what the plane says when entered in.. I remember when I was flying the -700 for awhile I noticed they didn't quite match up as good..
Well, last week I finally moved up to the pmdg B77L and now they are really wacked. Like not even close. The N1% topcat is requiring works fine, but how to get there doesn't. eg: it will tell me TO-2 +70C to get 89.1% N1.. but if I select to-2 and +70 it gives me something like 80.5% N1 or some shit.. first couple flights i didn't really notice what the problem was, I was wondering why "god damn i'm really rolling long here".. I have trusted topcat so much for the b738 that it didn't occur to me, until i started looking a the N1%
any ideas other than just fudging the assumed temp until its close to the required n1 ?
There is an intersection near my house that consistently fools Waze into thinking it will be the fastest throughpoint.
I know that intersection is one of the slowest traffic lights in the neighborhood. I commonly wait ~10 minutes to get through that single light.
The problem is that I have to go through this intersection if I want to go my alternate route to work... So, when I'm on my way, and I see that Waze is routing me through that intersection, I don't know if it is doing so because it's just trying to save me a minute (and cost me 9 in the process), or it is because my main route is congested further ahead.
I'd like to apply a 5-7 minute derate through that intersection so that Waze would only take me through there if it really needed to do so. Is that supported?
