SAP Tables

Functions and constants implementing various SAP tables

Hide the implementation details of the tables inside this package

Import the relevant functions as needed by other parts of saptk. When you add, modify, or remove functions from the tables modules, you must make the corresponding change in this file.

Aim to reduce the API surface of tables over time by encapsulating functionality inside it, and reducing the number of imports into this file.

epctk.tables.tables_.system_efficiency(system_data, fuel)[source]

Try to get the efficiency of the given heating sustem

Parameters:
  • system_data – HeatingSystem
  • fuel – fuel of this heating system.
  • todo (.) – why can’t we just get the fuel from the system?

Returns:

epctk.tables.tables_.table_1b_daily_hot_water(Nocc, low_water_use)[source]

Table 1b part 2: Domestic hot water usage

  1. Annual average hot water usage in litres per day Vd,average = (25 × N) + 36

  2. Reduce the annual average hot water usage by 5% if the dwelling is designed to achieve a water use target of not more that 125 litres per person per day (all water use, hot and cold)

  3. For each month, multiply Vd,average by the factor from Table 1c to obtain the daily volume in the month Vd,m

  4. The energy content of water used is

    4.190 × Vd,m × nm × ∆Tm / 3600 kWh/month

    where ∆Tm is the temperature rise for month m from Table 1d.

  5. Distribution loss is 0.15 times energy content calculated in (d).

This function calculates parts a) and b)

Parameters:
  • Nocc – Number of Occupants (from Table 1b part 1)
  • low_water_use (bool) – Whether the dwelling is designed to save water (see point b)
Returns:

Average daily hot water use
epctk.tables.tables_.table_1b_occupancy(TFA)[source]

Table 1b Part 1: Occupancy

if TFA > 13.9: N = 1 + 1.76 × [1-exp (-0.000349 × (TFA-13.9)2 )] + 0.0013 × (TFA-13.9)

if TFA ≤ 13.9: N=1

Parameters:TFA – Total Floor Area
Returns:Assumed number of occupants
Return type:int
epctk.tables.tables_.table_2_hot_water_store_loss_factor(hw_cylinder_insulation_type, hw_cylinder_insulation)[source]

Table 2

Calculate Hot water storage loss factor according to equation in Note 1. of Table 2 (rather than using the tabulated values)

Parameters:
  • hw_cylinder_insulation_type (CylinderInsulationTypes) –
  • hw_cylinder_insulation – thickness of cylinder insulation in mm
Returns:

hot water storage loss factor in kWh/litre/day
epctk.tables.tables_.table_2a_hot_water_vol_factor(cylinder_volume)[source]

Table 2a

Calculate the volume factor according to equation in Note 2. of Table 2a When using Table 2, the loss is to be multiplied by the volume factor.

Parameters:cylinder_volume – volume of hot water cylinder
Returns:hot water volume factor
epctk.tables.tables_.table_2b_hot_water_temp_factor(dwelling, measured_loss)[source]

Calculate the hot water temperature factor according to Table 2b

Parameters:
  • dwelling (Dwelling) –
  • measured_loss – boolean, whether the losses are measured by manufacturer or must be assumed

Returns:

epctk.tables.tables_.table_5a_fans_and_pumps_gain(dwelling)[source]

Table 5a gains from pumps and fans :param dwelling:

Returns: