enerhabitat 0.1.8

Paquete instalable para EnerHabitat

EnerHabitat

Tools for evaluating the thermal performance of structures based on EPW files

Contents

• Installation
• Recommended structure
• Key concepts
• Quickstart
• Main Structures
  • Location
  • System
  • Config
• Materials
• Dependencies
• License

Getting started

enerhabitat is a Python package for thermal simulation of constructive systems based on meteorological data from EPW files. The values that are calculated include:

• Ta : Ambient temperature
• Tsa : Sun-air temperature
• Ti : Interior temperature
• Ig : Global horizontal irradiance
• Ib : Direct normal irradiance
• Id : Diffuse horizontal irradiance
• Is : Surface irradiance

Installation

The source code is currently hosted on GitHub at EnerHabitat

Binary installers for the latest released version are available at the Python Package Index PyPI

pip install enerhabitat

If you're working with the uv Python package manager you can use the following

$ uv add enerhabitat

Folder structure

The following shows the basic folder structure recommended

├── main.py
├── materials.ini   # Materials properties
└── epw
    ├── ...
    └── example_file.epw

Key concepts

• Location reads an EPW file and computes the average day with meanDay().
• System uses a Location and a list of layers to compute Tsa, solve, and solveAC.
• config is a global instance. Modify config's attributes to change all subsequent computations behavior.

Quickstart

import enerhabitat as eh

# 1) Global configuration
# eh.config.file = "./materials.ini"

# 2) Location
epw_file = "./epw/example.epw"
loc = eh.Location(epw_file)

# 3) Constructive system
wall = eh.System(location=loc)
wall.layers = [("Adobe", 0.2)]

# 4) Solve
tsa = wall.Tsa()
ti = wall.solve()

Main structures

Load the EnerHabitat package for use

import enerhabitat as eh

Location

Create a location object from an EPW file.

epw_file = "./epw/example.epw"
loc = eh.Location(epw_file)

Attributes

The EPW path is stored infile, other Location read-only values include:

• city : str with the city of the EPW header.
• latitude : float value in degrees.
• longitude : float in degrees.
• altitude : float value in meters.
• timezone : pytz.timezone object.

Read-only attributes are recovered from the file header, assign a new EPW file to file to modify them

loc.file = "./epw/other.epw"

Methods

• meanDay() Calculates the average-day DataFrame with Ta, Ig, Ib, Id, and Tn.
• copy() Returns a copy of the instance
• info() Prints instance attributes
• flag() Dict with the last meanDay() computation values

Examples:

loc.meanDay(month="6", year=2020).info()
loc.info()
print(loc.flag()["date"])

System

Models a constructive system and computes interior temperatures. Crate a System from a Location object

loc = eh.Location("./epw/example.epw")
wall =  eh.System(location = loc)

Attributes

• location : Associated Location object
• tilt : float
• azimuth : float
• absortance : float
• layers : list with (material, width) tuples

wall.location = loc_2
wall.tilt = 0
wall.azimuth = 45,
wall.absortance = 0.3)

# Layers from outside to inside
wall.layers = [("Adobe", 0.10), ("Acero", 0.05), ("Ladrillo", 0.02)]

# Add and remove layers
wall.add_layer("Mortero", 0.20)
wall.remove_layer(2)

Other computation result values are stores as read-only attributes, this include:

• energy_transfer : Total energy transfer computed in solve()
• heating_energy : Total heating energy need computed in solveAC()
• cooling_energy : Total cooling energy need computed in solveAC()

Methods

• Tsa() computes Tsa and Is based on Location.meanDay()
• solve() computes Ti for the constructive system's layers
• solveAC() computes cooling and heating energy with constant Ti
• copy() returns a copy of the instance
• info() prints attributes
• flag() tells whether the cached value was recalculated

Examples:

# Tsa
wall.Tsa().info()

# Computation internal temperature
ti = wall.solve()
energy = wall.energy_transfer

# Computation Air conditioning
wall.solveAC()
c_energy = wall.cooling_energy
h_energy = wall.heating_energy

Config (global)

config stores parameters shared by all instances.

Note: this is global. Changing it affects future computations for any Location or System.

Attributes:

• file: Path to .ini file containing material's name and propertys
• La : length of the fictional room
• Nx : Number of elements to discretize the construction system
• ho : Outside convection heat transfer
• hi : Inside coonvection heat transfer
• dt : Time step inseconds

Example:

# Change materials file
eh.config.file = "./materials.ini"

# Update parameters
eh.config.La = 2.0
eh.config.Nx = 300
eh.config.ho = 12
eh.config.hi = 8.3
eh.config.dt = 60

Additionally config stores materials propertys in the read-only materials attribute in the form of a dict with the names of materials as keys and their properties k, rho and c class attributes

eh.config.materials

# Prueba con un solo material
adobe = eh.config.materials["Adobe"]

adobe.rho
adobe.c
adobe.k

Methods

• info() prints current config values
• to_dict() returns config parameters as a dict
• reset() restores default config values
• materials_list() returns the material names defined in file
• materials_dict() returns a dict of material properties

Materials

The material's name and their properties are specified in the materials.ini configuration file, specifying the material name as the key and its values ​​for k, rho and c.

[concrete]
k   = 1.35  # Overall heat transfer coefficient
rho = 1800  # Density
c   = 1000  # Specific heat

[adobe]
k   = 0.58
rho = 1500
c   = 1480

To set a configuration file, use the config.file attribute and specify the path.

eh.config.file = "./config/new_materials.ini"

Dependencies

• numba
• pvlib
• numpy
• pandas
• pytz

License

Code released under the MIT license.