This is the multi zone residential hydronic emulator model of BOPTEST.

Building Design and Use

Architecture

The emulator building model represents a residential French dwelling compliant with the French Thermal regulation of 2012, i.e. the French national building energy regulation. Therefore, the typology is defined to be representative of French new dwellings. The area not including the unconditioned attic and unconditioned garage is of 81.08 m². The following figure shows the building layout and a sketch of the hydraulic system. The coloured elements in the scheme represent the controllable components through the BOPTEST interface. The dimensions are provided in metres.

Simulated residential dwelling

The orientation of each building was chosen to maximize the natural light during winter. Thus, the main surface of windows of the building is south oriented. The building consists of six thermal zones that are actively controlled and two unconditioned zones:

The building envelope was defined in order to cover the new construction modes existing on the market. Thus, each of these modes was characterized by a different level of insulation (Table 1).

Table 1.Building envelope characteristic


Wall type

Characteristics

External wall

Brick (200 mm, λ=0.2 W/mK) + polystyrene (80 mm, λ=0.032 W/mK)




U = 0.272 W.m-2.K-1

Floor

Hollow block (150 mm, λ=0.92 W/mK) + polyurethane (60 mm, λ=0.022 W/mK)



Ue = 0.327 W.m-2.K-1

Ceiling

Glass wool (200 mm, λ=0.04 W/mK)



U = 0.193 W.m-2.K-1

Fenestration

Double glazing with Argon and PVC frame 4/16/4, Planitherm glass g=0.6, TL=76% with external solar protection



Uw = 1.40 W.m-2.K-1

These values are in accordance with the French Thermal regulation 2012. The building was subject to a detailed modeling according to the architecture plans. The volume was divided into 8 thermal zones according to space function (an additional thermal zone was created to simulate the behaviour of the attic). Each space (room) has its own thermal behaviour as a result of the boundary conditions (climate, adjacent spaces, etc.) and the internal conditions (internal loads, scenarios, etc.)

The thermal bridges effect is modeled through thermal resistances that are parameterized with the length of the bridge element and a thermal coefficient (k_PT).

Occupancy schedules

The thermal zones of the building, except the unheated zones, are subject to conventional scenarios (occupation, heating, cooling, ventilation, lighting, internal loads) defined in the French Thermal Regulation 2012 (CSTB - Centre Scientifique et Technique du Bâtiment), 2012. Méthode de calcul Th-BCE - Réglementation thermique 2012; CSTB, 2012).

For example, the building is considered occupied continuously by four adults from 19PM to 10AM for 4 weekdays, from 15PM to 10AM during all Wednesdays and all day long during weekends. During the periods that the building is occupied, the occupants are considered to be either all in the living room during day-time, or distributed in their rooms during night-time. There is a short transition period (one hour) on the switching between day- and night-time when the living room and bedrooms are considered to be occupied to half of their nominal capacity each. A reduction of 30% of the internal loads due to occupants is observed during the night-time.

On a yearly basis, the building is considered unoccupied one week at the end of December and two weeks in August.

The building heating temperature setpoint is fixed conventionally at 19°C during occupied periods, 16°C during unoccupied periods shorter than 48 hours and 7°C otherwise. The scenario for cooling is similar, cooling temperature setpoints are 28°C / 30°C / 30°C.

Internal loads and schedules

The internal loads considered are mainly due to lighting and appliances. For lighting, approximately 1.1 W/m² are considered according to CSTB - Centre Scientifique et Technique du Bâtiment, 2012 Méthode de calcul Th-BCE - Réglementation thermique 2012; CSTB, 2012, 80% of the 1.1 W/m² installed power is transformed in heat. Appliances contribution to internal loads are considered at a level of 5.7 W/m² from 7AM to 10AM and from 19PM to 22PM for 4 weekdays, 7AM to 10AM and from 15PM to 22PM during all Wednesdays and all day long during weekends. Otherwise, this level is reduced by 80%.

Climate data

The model uses a climate file containing one year of weather data for Bordeaux, France (FRA_Bordeaux.075100_IWEC.mos). The ground temperature is assumed to be a sinusoidal signal with an amplitude of 2°C oscilating with a yearly period around 15°C.

HVAC System Design

Primary and secondary system designs

Each building zone has its own radiator equipped with a thermostatic valve that is modeled using a PI controller. The radiators are sized accordingly to the building envelope characteristics and to the specific climate of Bordeaux, France.

The water through the heating emission system is heated by a gas boiler. The boiler is designed to provide power (sum of the radiators nominal power) for spacial heating only, domestic hot water production is not taken into account in this model.

The building is in cooling mode until March 29th (day 88 of the year), and from October 28th (day 301 of the year). During this period, ideal cooling is considered in all conditioned zones with a PI controller in each zone. This controller provides the cooling thermal power required to comply with the cooling setpoint in every zone.

Equipment specifications and performance maps

The boiler uses an efficiency curve constant with coefficient 0.9. The heating system circulation pump uses an efficiency curve that is function of the mass flow rate of water through the emission system. Air cooling is modeled with a constant energy efficiency ratio of 3.

Rule-based or local-loop controllers (if included)

The following set of controllers drive the baseline controller implemented in this model:

Model IO's

Inputs

The model inputs are:

Outputs

The model outputs are:

Forecasts

The model forecasts are:

Additional System Design

Lighting

For lighting, approximately 1.1 W/m² are considered according to CSTB - Centre Scientifique et Technique du Bâtiment, 2012 Méthode de calcul Th-BCE - Réglementation thermique 2012; CSTB, 2012, 80% of the 1.1 W/m² installed power is transformed in heat.

Shading

No shading model is included.

Model Implementation Details

Moist vs. dry air

The model uses moist air despite that no condensation is modeled in any of the used components. Also, latent heat gain by occupants is not modeled.

Pressure-flow models

A circulation loop with one parallel branch per zone is used to model the heating emission system.

Infiltration models

Mechanical ventilation from outside air and air exchange between zones are considered in the model. The total value of the volumetric airflow exchanged is established according to the French national regulations. Specifically, outside fresh air is infiltrated in the garage and the attic at a rate of 0.5 ACH. In the living room and bedrooms the total infiltrated air is of 113.4 m3/h, which is distributed proportionally to the area of these zones. There is not infiltration considered in the bathroom nor the hallway. 80% of the infiltrated air is exhausted through a fan in the bathroom. This fan is not controllable and its electricity use is neglected. The other 20% of the infiltrated air is assumed to be leaked in the living room.

Other assumptions

The CO2 generation in each zone is based on number of occupants in that zone. CO2 generation is 0.004 L/s per person (Table 5, Persily and De Jonge 2017) and density of CO2 assumed to be 1.8 kg/m^3, making CO2 generation 7.2e-6 kg/s per person. Outside air CO2 concentration is 400 ppm. However, CO2 concentration is not controlled for in the model.

Persily, A. and De Jonge, L. (2017). Carbon dioxide generation rates for building occupants. Indoor Air, 27, 868–879. https://doi.org/10.1111/ina.12383.

Scenario Information

Time Periods

The Peak Heat Day (specifier for /scenario API is 'peak_heat_day') period is:

The Typical Heat Day (specifier for /scenario API is 'typical_heat_day') period is:

Energy Pricing

All pricing scenarios include the same constant value for transmission fees and taxes of each commodity. The used value is the typical price that household users pay for the network, taxes and levies, as calculateed by Eurostat and obtained from: "The energy prices and costs in Europe report". For the assumed location of the test case, this value is of 0.125 EUR/kWh for electricity and of 0.042 for gas.

Constant electricity price profile
(specifier for /scenario API is 'constant') profile is:

The constant electricity price scenario uses a constant price of 0.108 EUR/kWh, as obtained from the Engie's "Elec Ajust" deal before taxes (HTT) in https://particuliers.engie.fr/content/dam/pdf/fiches-descriptives/fiche-descriptive-elec-ajust.pdf (accessed on July 2020). The tariff used is the one for households with contracted power installations higher than 6 kVA. Adding up the transmission fees and taxes, the final constant electricity price is of 0.233 EUR/kWh.

Dynamic electricity price profile
(specifier for /scenario API is 'dynamic') profile is:

The dynamic electricity price scenario uses a dual rate of 0.126 EUR/kWh during day time and 0.086 EUR/kWh during night time, as obtained from the the Engie's "Elec Ajust" deal before taxes (HTT) in https://particuliers.engie.fr/content/dam/pdf/fiches-descriptives/fiche-descriptive-elec-ajust.pdf (accessed on July 2020). The tariff used is the one for households with contracted power installations higher than 6 kVA. The on-peak daily period takes place between 7:00 a.m. and 10:00 p.m. The off-peak daily period takes place between 10:00 p.m. and 7:00 a.m. Adding up the transmission fees and taxes, the final dynamic electricity prices are of 0.251 EUR/kWh during on-peak periods and of 0.211 during off-peak periods.

Highly dynamic electricity price profile
(specifier for /scenario API is 'highly_dynamic') profile is:

For the highly dynamic scenario, the French day-ahead prices of 2019 are used. Obtained from: https://www.epexspot.com/en The prices are parsed and exported using this repository: https://github.com/JavierArroyoBastida/epex-spot-data. Notice that the same constant transmission fees and taxes of 0.125 EUR/kWh are added up on top of these prices.

Gas price profile

The gas price is assumed constant and of 0.0491 EUR/kWh as obtained from the "Gaz Energie Garantie 1 an" deal for gas in https://particuliers.engie.fr/content/dam/pdf/fiches-descriptives/fiche-descriptive-sommaire-gaz-energie-garantie.pdf (accessed on July 2020). Price before taxes (HTT) for a contracted anual tariff between 0 - 6000 kWh. Adding up the transmission fees and taxes the final constant gas price is of 0.0911 EUR/kWh.

Emission Factors

Electricity emissions factor profile

It is used a constant emission factor for electricity of 0.047 kgCO2/kWh which is the grid electricity emission factor reported by the Association of Issuing Bodies (AIB) for year 2019 in France. For reference, see: https://www.carbonfootprint.com/docs/2019_06_emissions_factors_sources_for_2019_electricity.pdf

Gas emissions factor profile

Based on the kgCO2 emitted per amount of natural gas burned in terms of energy content. It is 0.18108 kgCO2/kWh (53.07 kgCO2/milBTU). For reference, see: https://www.eia.gov/environment/emissions/co2_vol_mass.php