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We have seen estimates suggesting that LED’s use an average of 80% as much energy as an equivalent CFL. Using this conversion (or another of your choosing) you could model each LED bulb as 0.8 of a CFL bulb. The control will handle a fractional entry even though it doesn’t display the digits. You will obviously have to edit the cost manually as well.
Hi Bruce,
That’s a tough one. I’m sorry we don’t have that option in our standard selections. We haven’t run into a good resource for modeling that scenario. As I understand it the seasonal efficiency of the water heating will depend heavily on the house heating dynamics. You can model a workaround by selecting the Oil Tank Water Heater option and modifying the Recovery Efficiency and Energy Factor yourself. The Recovery Efficiency will be something less than the AFUE of the boiler for heating purposes. How much less will depend on the size of the system (cycling losses) and how often it is simultaneously in use for home heating. The EF will be just a couple points lower than the Recovery Efficiency. The best case scenario would be when you have sufficient oil delivery data to get a good base load estimate. You could then calibrate the efficiency to match the utility usage.
If you are aware of any good resources on this issue, please pass them along.
That’s exactly right, Carlos. And if you don’t have the generation data, then it is better not to enter the electric bills at all. In complete usage data could have a very problematic impact on the utility analysis and model calibration.
I would not combine those for the utility analysis. The most important function of the utility analysis is to calculate a weather normalized heating and cooling usages. Combining a base-load-only fuel with a heating fuel would just muddy the analysis for the heating fuel. You can tally the annual propane usage yourself, check it against the DHW usage total in the model and then make appropriate calibration adjustments. (You can view the DHW usage by clicking the “Report…” button, opening the “Energy Analysis” frame on the popup, and clicking the “Load Table” button.
You may also want to view this topic on modeling wood heaters:
We do not currently have a way to specify refrigerator and freezer location. It is high on our list of desired features, but there are some larger projects ahead of it. I think it’s several months out at this point, but we will add it. Thanks for letting us know that it is important to you.
Calculating a decent estimate impact of continuous circulation would require a detailed analysis of the entire piping system including pipe diameter, flow rate, insulation level, pipe location, etc. This is well beyond the scope of OptiMiser’s DHW model and most audits. I also suspect that the potential results would vary too widely to put in a simple multiplier. I’ll put it on our long term wish list. If you are aware of any good research on the matter, please send it our way.
In the mean time, if you want to play around with your own estimates, the best way to simulate the effect would be to decrease the rated EF of the water heater, while leaving the recover efficiency unchanged. The constant re-circulation has the effect of increasing the tank UA, which decreases the EF.
You won’t be able to do this directly in OptiMiser. We do have controls to model ceiling fans. The are in the frame on the bottom of the Cooling tab labeled Fans. However, the fans are modeled per the RESNET standard to run at medium speed for 10.5 hours per day and only during cooling months where the average temperature is greater than 63F. If the fans are indeed running year round, then you could multiply the number of fans by the ratios 24h/10.5h and 12/CoolingMonths. Any change you make to the ceiling fans will be linked to the Cooling improvement, so you will have to check that row in the Details table to see the impact.
However, there are a couple of problems you should consider
- Turning off all of the fans is likely to alter the occupant behavior with the thermostat. They are likely very used to constantly circulating air and the temperature that they need to be comfortable may be different without it.
- Depending on the effectiveness of the HVAC distribution system, turning off all the ceiling fans could also have a significant impact on the temperature distribution in the home.
Neither of these impacts can be modeled.
- Set the Base DHW 1 system to the existing system.
- Set the % Total for the Improved DHW 1 system to 35%
- Set the specs for Improved DHW 1 system to those of the new backup system
- Set the % Total for Improved DHW 2 to 65%. This should happen automatically
- Set the Fuel for Improved DHW 2 to Solar.
If you change the fuel type to Propane at the top of the Utilities tab, then you should have unit options of CF and Gallon in the selector next to the first bill usage. If that is not the case, then please submit an error report using the red “!” button. Thanks!
EDIT: OptiMiser now offers direct support for multiple fuel types. On the Utilities tab, select “Multiple Fuels” in the Fuel Type control and then open the Multiple Fuel Entry popup. You can choose Start and End dates (preferably spanning at least one year) and then enter total usage for each fuel. The instructions below are still useful, if you feel that you can accurately describe multiple periods of combined usage.
At this point the utility analysis can handle electricity plus any one fuel. Simply specify on the Utility tab, whether the home uses Fuel Heat, Electric Heat, or Dual Heat. That will inform the utility analysis where to search for the heating signal. In the situation you describe, the analysis would get the heating, cooling, and electric base load (i.e. appliances) information from the electric bills and the one fuel base load information from the fuel bills.
For multiple heating fuels. you can work around this limitation by converting usage for a second fuel to the same energy units as the primary fuel. The tricky thing about doing this is that the delivery schedules will probably be different. You will probably have to combine multiple bills to achieve a period with known total usage. You may even need to combine all of them into one period covering the entire heating season. It would be helpful to read the section on “delivered” fuels in the Utilities help. Here are the Btu equivalents for a selection of heating fuels:
Natural Gas (MCF) – 1,025,000
Natural Gas (Therm) – 100,000
Natural Gas (MBtu) – 1,000,000
Electricity (kWh) – 3,412
Propane (CF) – 2,539
Propane (Gallon) – 91,330
Fuel Oil (Gallon) – 140,000
Wood (Cord) – 20,000,000
Wood (Pound) – 8,000
Pellets (Ton) – 16,500,000
Pellets (Pound) – 8,250
Kerosene (Gallon) – 135,000
Coal (Ton) – 28,000,000
