Updating hot water fixtures multipliers based on field data.

afontani commented 7 months ago

Pull Request Description

Companion PR: resstock-estimation PR #361

Update hot water usage multipliers. Using field data from 1700 water heaters in New England to come up with the distribution. Based on data collected as part of PERFORM with Michael Blonsky, who shared the distribution with us.

Distribution Information

    mean = 0.8  # average multiplier is 80%
    stdev = 0.2  # std dev of lognormal distribution is 20% (i.e. 95% CI is about 0.4-1.2)
    u = np.log(mean**2 / (mean**2 + stdev**2)**0.5)
    s = np.log(1 + stdev**2 / mean**2)**0.5
    usage_multiplier = np.random.lognormal(u, s)

Checklist

Not all may apply:

[ ] Tests (and test files) have been updated
[ ] Documentation has been updated
- [ ] If related to resstock-estimation, checklist includes data dictionary, source report, options saturation, options_lookup.
[x] Changelog has been updated
[ ] openstudio tasks.rb update_measures has been run
[ ] No unexpected regression test changes on CI (checked comparison artifacts)

afontani commented 7 months ago

From the artifacts here is the change in water outputs:

	Base	Base	Feature	Feature	Diff	Diff	Diff %	Diff %
Outputs	project_national	project_testing	project_national	project_testing	project_national	project_testing	project_national	project_testing
Average of report_simulation_output.end_use_electricity_hot_water_m_btu	1.97939	3.382172	2.15735	2.623208	-0.17796	0.758964	-9.0%	22.4%
Average of report_simulation_output.end_use_natural_gas_hot_water_m_btu	3.04222	9.303564	3.70332	7.983112	-0.6611	1.320452	-21.7%	14.2%
Average of report_simulation_output.hot_water_clothes_washer_gal	375.623	980.7772	375.638	980.778	-0.015	-0.0008	0.0%	0.0%
Average of report_simulation_output.hot_water_dishwasher_gal	436.613	707.5804	436.546	707.5808	0.067	-0.0004	0.0%	0.0%
Average of report_simulation_output.hot_water_distribution_waste_gal	1588.791	3777.764	1694.943	2883.6764	-106.152	894.0876	-6.7%	23.7%
Average of report_simulation_output.hot_water_fixtures_gal	9959.655	10937.5604	10477.665	8352.7808	-518.01	2584.7796	-5.2%	23.6%
Average of report_simulation_output.load_hot_water_delivered_m_btu	6.38513	8.501804	6.70669	6.69442	-0.32156	1.807384	-5.0%	21.3%
Average of report_simulation_output.load_hot_water_tank_losses_m_btu	1.89666	2.535488	1.89532	2.535424	0.00134	6.4E-05	0.1%	0.0%

afontani commented 7 months ago

After a follow-up conversation with @jmaguire1, it seems that the data above is not representative. We split out the usage by electricity and gas. The expected reduction according to the TSVs is 26.5%. The gallon reduction is approximately 26% for both natural gas and electric water heaters. The energy percent reduction is less than the 26.5% as there is additional energy needed for tank losses.

ELECTRIC WATER HEATERS	Base	Feature	Diff	Diff %
Average of report_simulation_output.end_use_electricity_hot_water_m_btu	9.1	7.1	-2.0	-22%
Average of report_simulation_output.end_use_natural_gas_hot_water_m_btu	0.0	0.0	0.0	0%
Average of report_simulation_output.hot_water_clothes_washer_gal	1043.5	1043.5	0.0	0%
Average of report_simulation_output.hot_water_dishwasher_gal	789.5	789.5	0.0	0%
Average of report_simulation_output.hot_water_distribution_waste_gal	3919.0	2822.6	-1096.4	-28%
Average of report_simulation_output.hot_water_fixtures_gal	11316.4	8202.0	-3114.5	-28%
Average of report_simulation_output.load_hot_water_delivered_m_btu	8.1	6.1	-2.0	-25%
Average of report_simulation_output.load_hot_water_tank_losses_m_btu	0.9	0.9	0.0	0%
Total hot water draw	17068.4	12857.5	4210.9	25%

NATURAL GAS WATER HEATERS	Base	Feature	Diff	Diff %
Average of report_simulation_output.end_use_electricity_hot_water_m_btu	0.0	0.0	0.0	0%
Average of report_simulation_output.end_use_natural_gas_hot_water_m_btu	20.6	16.9	-3.7	-18%
Average of report_simulation_output.hot_water_clothes_washer_gal	390.7	390.7	0.0	0%
Average of report_simulation_output.hot_water_dishwasher_gal	520.1	520.1	0.0	0%
Average of report_simulation_output.hot_water_distribution_waste_gal	2280.6	1742.0	-538.6	-24%
Average of report_simulation_output.hot_water_fixtures_gal	14703.4	10601.0	-4102.4	-28%
Average of report_simulation_output.load_hot_water_delivered_m_btu	9.4	7.1	-2.3	-25%
Average of report_simulation_output.load_hot_water_tank_losses_m_btu	2.1	2.1	0.0	0%
Total hot water draw	17894.8	13253.7	-4641.0	-26%

NREL / resstock