Conversion technologies¶

Conversion technologies are systems that transform one or more energy carriers into different types. For example, a gas boiler converts natural gas to heat. Each technology is defined by:

• Technical parameters: efficiencies and technical limits.
• Financial and environmental parameters: investment costs (CAPEX), operational costs (OPEX), and embodied emissions.

For parameters, see Conversion technology parameters.

Technology modes¶

A mode represents a specific operational regime with its own set of inputs, outputs, and efficiencies. A single technology can have multiple modes to reflect different operating regimes.

Example: a reversible heat pump has a heating mode and a cooling mode, each with a distinct coefficient of performance (COP). Only one investment is made and two behaviors are possible.

Primary vs. non-primary modes¶

• Primary mode: has an impact on the installed capacity of the technology, which is reflected in the costs and CO2 emissions.
• Non-primary mode: does not affect the installed capacity of the technology. The technology's investment or operational costs, or its CO2 emissions are not affected by the capacity of non-primary modes.

Mode capacity¶

The capacity of a mode is the maximum of the hourly sum of all primary outputs of that mode.

You can choose different sizing methods:

• Optimize capacity: Sympheny finds the optimal capacity.
• Minimum and Maximum capacity: You can enter a minimum and/or maximum capacity bound.
• Can be installed and Minimum capacity: If a minimum capacity is specified and the default option is toggled, the installed capacity can either be 0 or greater than the minimum.
• Must be installed and Minimum capacity: The capacity must be greater than or equal to the minimum capacity.
• Specify capacity: The installed capacity is fixed. If the default "can be installed" option is toggled, the capacity will be either 0 or the specified capacity.

Technology capacity¶

The installed capacity of the technology is used to calculate the investment, maintenance costs, and embodied emissions. The technology capacity is the maximum of the hourly sum of all primary outputs of all primary modes. It is expressed in kW-output.

Example calculation¶

• Mode A peak (primary): 100 kW at hour 5.
• Mode B peak (primary): peak of 200 kW at hour 10.
• Mode A + Mode B peak: at hour 8, modes A and B produce a combined 250 kW.

Result: the technology capacity is 250 kW.

Mode efficiency¶

The efficiency of a mode indicates energy dissipation within systems. The sum of output efficiencies represents the mode's total efficiency:

• A total efficiency of 100% means useful energy is conserved.
• A total efficiency below 100% indicates useful energy is lost in the system, for example heat losses in the technology, which are not modeled as a "waste heat" flow.
• A total efficiency above 100% indicates useful energy is created within the system, for example useful heat extracted from the environment, which is not modeled as an "ambient air" flow.

Example: heat pump¶

The efficiency of a standard input (with two inputs) is set as follows:

The calculation is:

Output EC(i) = Sum of inputs × efficiency output(i)

HT heat = (100 + 200) × 100% = 300

In this case, 100 units of electricity and 200 units of ambient heat produce 300 units of HT heat. This corresponds to a COP of 3 (yearly average). See illustration below on how to set these parameters in the web-app.

Example: chiller¶

For chillers, there are two ways to model cooling energy. The first method treats cooling energy as a service, meaning the energy is generated and supplied. For example, when modeling a chiller with an energy efficiency ratio (EER) of 2, the process is as follows:

This means that an input of 100 units of electricity produces 200 units of cooling (based on an EER of 2) and 300 units of heating (assuming the electricity is fully dissipated as heat).

100 units of electricity give, in this case, 300 units of HT heat and 200 units of cooling, from which an EER of 2 is calculated. Here, the cumulative output efficiency is greater than 100%, which reflects the "creation" of energy because cooling energy is treated as an additional service. See illustration below on how to set these parameters in the web-app.

Alternative method: chiller¶

There's also an alternative method where cooling energy is treated as an extraction of energy demand. To use this method, set the cooling demand to "reversed." In this case, the chiller can be modeled as a heat pump with an EER of 2 (or a COP of 3).

See illustration below on how to set these parameters in the web-app.

Simultaneity of operation¶

Different modes can operate simultaneously. To prevent this, leave the simultaneous checkbox unchecked, indicating the mode cannot run with others. This may increase optimization time.

Alternatively, a less computationally intensive option is to define a different seasonal or hourly operation for each mode.

Some advanced parameters are not available to all plan tiers, but can be added through add-on options. Contact customer support for a demo and to discuss customizing these options to your needs.

Seasonal and hourly parameters¶

You can enter time-varying efficiencies, either as monthly or hourly values. To do so, select Time varying instead of Fixed for the output EC efficiency.

Example: air-source heat pump¶

For heat pumps, if you want to apply a time-varying COP, modify the input EC share rather than the output efficiency. The input EC share is what defines the COP (= heat HT / electricity). See the example below: