Buffers
All space heating and hot water demand in ETMoses is supplied through a so-called buffer. ETMoses contains two types of buffers; one for space heating and one for hot water which can be added in the technology matrix. A profile has to be assigned to these buffers describing the space heating or hot water demand for each time step throughout the year. Several pre-defined profiles are available in ETMoses. In addition to a profile, a (storage) volume needs to be assigned to the buffer to describe how much energy the buffer can store. This volume can be 0 to represent the case when there is no buffer. The user can also assign cost to the buffers themselves, this isn't done automatically. Since ETMoses uses separate buffers for hot water and heating, there is a risk of [double-counting the costs] (https://github.com/quintel/etmoses/wiki/Technologies#double-counting-of-depreciation-costs-for-space-heating-and-hot-water-technologies).
Heat can be supplied to these buffers by the following heating technologies. Details of these technologies can be found in the respective sections of this Wiki.
These technologies are either boosting or buffering. Boosting technologies fulfill the space heating or hot water demand instantly. Buffering technologies fill the buffer, such that the energy content of the buffer can be used to meet the demand for space heating or hot water at a later moment. Several strategies are available to make efficient use of the available storage volume in the buffers.
Three attributes are important in describing a buffer: the output capacity, the demand and the volume.
- The output capacity is defined as the amount of energy that can be extracted from the buffer per unit of time; the default value is
10 kW. - If the buffers are inherited from the energy scenario in the Energy Transition Model, the demand is set to the average annual space heating or hot water demand per household. If a new buffer is added, the demand is left blank and it is up to the user to fill out this attribute
- The volume per buffer (in kWh) is the equivalent of heating 100 liter of water from 15 degrees centigrade to 40 degrees and 50 degrees centigrade for space heating and hot water respectively
Note that hybrid heat pumps should be assigned their own buffer as discussed in more detail in https://github.com/quintel/etmoses/issues/1159.
Each household generally has two buffers that contain heat: one for space heating and one for domestic hot water consumption. The buffers are linked to a demand/use profile which describes how much energy is requested by the household in every time step. This heat can be fulfilled by the buffer and/or other heating technologies. One or more technologies can be attached to a buffer to 'charge' it.
The buffers are characterised by the following specifications:
| Buffer |Size| T_min |T_max |Profiles | Allowed technologies | |---|---|---|---|---|---|---|---| |Space heating|100 liter *|15|40|heating demand|space heating technologies| |Domestic hot water|100 liter *|15|50|hot water demand|hot water technologies|
Buffers must be associated with profiles which describe the demand. Profiles describing space heating demand and hot water demand are characterised by 35040 values which are normalised such that the suface area under their 'curve' is 1/4. If the curves are later 'scaled' with the yearly demand for heat (in kWh), the resulting curve represents the instantaneous heat demand in kW for each 15 minute interval of the year.
The default profiles in ETMoses are described in the Profiles section.
The buffer for space heating is heated by buffering technologies to the energetic equivalent of 40 degrees.
|Technology|Buffering|Boosting|Comments| |---|---|---|---|---| |households_space_heater_heatpump_air_water_electricity|yes|no|| |households_space_heater_heatpump_ground_water_electricity|yes|no|| |households_space_heater_hybrid_heatpump_air_water_electricity|yes|no|the e-part| |households_space_heater_hybrid_heatpump_air_water_gas|no|yes|the gas-part| |households_space_heater_network_gas|no|yes|| |households_space_heater_combined_network_gas|no|yes|| |households_space_heater_electricity|yes?|yes|currently not inculded!|
The buffer for hot water is heated by buffering technologies to the energetic equivalent of 50 degrees.
|Technology|Buffering|Boosting|Comments| |---|---|---|---|---| |households_water_heater_heatpump_air_water_electricity|yes|no|| |households_water_heater_heatpump_ground_water_electricity|yes|no|| |households_water_heater_hybrid_heatpump_air_water_electricity|yes|no|the e-part| |households_water_heater_hybrid_heatpump_air_water_gas|no|yes|the gas-part| |households_water_heater_network_gas|no|yes|| |households_water_heater_combined_network_gas|no|yes|| |households_water_heater_electricity|yes?|yes|currently not included!| |households_flexibility_p2h_electricity|yes|no||
