Benefit:<\/strong> Correct curve configuration eliminates overheating in mild weather and underheating in cold periods.<\/p>\nExample:<\/strong> An iDM TERRA HGL heat pump installed with underfloor heating in a 2018-built Austrian Niedrigenergiehous uses a heating curve slope of 0.4 with a design flow temperature of 33 \u00b0C. This allows the system to run at COP values above 4.5 during the heating season.<\/p>\nBivalence Point (Bivalenzpunkt)<\/h3>\n
Definition:<\/strong> The bivalence point is the outdoor temperature at which the heat pump’s capacity equals the building’s heat load.<\/p>\nPurpose:<\/strong> It defines the switching behavior of hybrid or bivalent systems. Below this temperature, a backup heater (electric immersion heater, gas boiler, or biomass unit) supplements or replaces the heat pump.<\/p>\nKey setup decisions:<\/strong><\/p>\n\n- Monovalent operation:<\/strong> No backup heat source. The heat pump covers 100% of heat demand. Suitable for well-insulated buildings.<\/li>\n
- Bivalent-parallel operation:<\/strong> Backup heater operates simultaneously with the heat pump below the bivalence point.<\/li>\n
- Bivalent-alternative operation:<\/strong> Heat pump switches off; backup heater takes over completely.<\/li>\n<\/ul>\n
Benefit:<\/strong> Correct bivalence point configuration prevents the backup heater from activating unnecessarily, minimizing operating costs.<\/p>\nExample:<\/strong> In South Tyrol (Italian Alps), a building with a design temperature of -12 \u00b0C and a heat pump rated at 8 kW heating capacity may have its bivalence point set at -5 \u00b0C. Below -5 \u00b0C, an electric auxiliary heater assists to cover peak loads on the coldest days of the year \u2014 typically fewer than 50 hours annually.<\/p>\nDomestic Hot Water (DHW) Parameters<\/h3>\n
Definition:<\/strong> DHW parameters define the target temperature, heating schedule, and anti-Legionella cycle for the domestic hot water system.<\/p>\nPurpose:<\/strong> The heat pump must heat drinking water to usable temperatures while minimizing energy consumption. It must also meet hygiene requirements defined in standards such as DVGW W 551<\/strong> (Germany) and \u00d6NORM B 5019<\/strong> (Austria).<\/p>\nKey parameters to configure:<\/strong><\/p>\n\n- DHW target temperature:<\/strong> Typically 45\u201355 \u00b0C for heat pumps. Higher temperatures significantly reduce COP.<\/li>\n
- DHW heating time window:<\/strong> Schedule when DHW heating runs \u2014 typically overnight during off-peak electricity tariff periods.<\/li>\n
- Legionella protection cycle:<\/strong> A periodic heat-up to \u226560 \u00b0C to eliminate Legionella bacteria. Required by regulation. Typically runs once per week.<\/li>\n
- DHW priority:<\/strong> Defines whether DHW heating interrupts space heating. Options include full priority, parallel operation, or time-limited priority.<\/li>\n<\/ul>\n
Benefit:<\/strong> Properly scheduled DHW parameters reduce electricity consumption by 10\u201320% compared to continuous heating mode.<\/p>\nOperating Temperature Limits<\/h3>\n
Definition:<\/strong> Upper and lower boundary temperatures that define the safe operating range of the system.<\/p>\nPurpose:<\/strong> These limits protect system components from thermal stress and prevent the heat pump from operating outside its design envelope.<\/p>\nParameters include:<\/strong><\/p>\n\n- Maximum flow temperature (Vorlauftemperatur max):<\/strong> Prevents overheating of the heating circuit. Typically 55\u201365 \u00b0C depending on system design.<\/li>\n
- Minimum return temperature:<\/strong> Protects the refrigerant circuit from low-pressure faults.<\/li>\n
- Minimum outdoor temperature for heat pump operation:<\/strong> Below a certain outdoor temperature (e.g., -20 \u00b0C), the heat pump switches to backup heating. This protects the compressor.<\/li>\n
- Frost protection limit:<\/strong> Activates pump circulation to prevent pipe freezing.<\/li>\n<\/ul>\n
Time Programs and Operating Modes<\/h3>\n
Definition:<\/strong> Time programs define when the heat pump operates, when it enters reduced-temperature (setback) mode, and when it performs specific tasks like DHW heating.<\/p>\nPurpose:<\/strong> Time-based control matches heat pump operation to occupancy patterns and electricity tariff structures.<\/p>\nConfiguration elements:<\/strong><\/p>\n\n- Heating periods:<\/strong> Define active hours for space heating per day and per zone.<\/li>\n
- Night setback temperature:<\/strong> Reduced room temperature target during sleeping hours. Typically 16\u201318 \u00b0C. Reduces overnight energy consumption.<\/li>\n
- Presence \/ absence mode:<\/strong> Manual or automated switching when the building is unoccupied.<\/li>\n
- Smart meter integration:<\/strong> Time programs can be synchronized with dynamic electricity tariffs (e.g., Tibber, aWATTar) to favor operation during low-cost periods.<\/li>\n<\/ul>\n
Benefit:<\/strong> Optimized time programs reduce annual electricity costs by 8\u201315% in typical residential applications.<\/p>\nPump and Hydraulic Parameters<\/h3>\n
Definition:<\/strong> Settings that control the behavior of circulation pumps within the heating system.<\/p>\nPurpose:<\/strong> Correct pump settings ensure adequate flow rates through the heat exchanger and heating circuits. Insufficient flow causes high temperature differentials (\u0394T) and reduces heat pump efficiency.<\/p>\nKey parameters:<\/strong><\/p>\n\n- Minimum flow rate (Mindestvolumenstrom):<\/strong> The minimum water volume the primary pump must circulate. Prevents low-flow faults.<\/li>\n
- Differential pressure setpoint:<\/strong> For variable-speed pumps, the target differential pressure across the heating circuit.<\/li>\n
- Buffer tank (Pufferspeicher) integration:<\/strong> Settings that define how the buffer tank is charged and discharged. A correctly sized buffer prevents short-cycling.<\/li>\n<\/ul>\n
Note:<\/strong> Hydraulic balancing \u2014 the physical adjustment of flow rates through each heating circuit \u2014 must be completed before parameter setup. Parameters cannot compensate for incorrect hydraulic design.<\/p>\nCompressor and Defrost Settings<\/h3>\n
Definition:<\/strong> Parameters that control compressor start behavior and the automatic defrost cycle for air-source heat pumps.<\/p>\nPurpose:<\/strong> The compressor requires a controlled start sequence to prevent mechanical stress. The defrost cycle removes ice from the outdoor evaporator during cold, humid conditions.<\/p>\nKey settings:<\/strong><\/p>\n\n- Minimum compressor run time:<\/strong> Prevents short cycling. Typically 5\u201310 minutes minimum.<\/li>\n
- Minimum off time:<\/strong> Compressor rest period between cycles to protect the refrigerant circuit.<\/li>\n
- Defrost initiation criteria:<\/strong> Temperature or time-based triggers for defrost cycles. Typically activated below +5 \u00b0C outdoor temperature with high humidity.<\/li>\n
- Maximum defrost duration:<\/strong> Prevents excessive heat extraction from the building during long defrost events.<\/li>\n<\/ul>\n
<\/span>Types of Heat Pump Systems and Parameter Differences<\/span><\/h2>\nDifferent heat pump technologies require different parameter configurations. The installer must adapt the setup process to the specific system type.<\/p>\n
Air-to-Water Heat Pumps (Luft-Wasser-W\u00e4rmepumpen)<\/h3>\n
The most common type in Austria, Germany, and Switzerland. Source is outdoor air. Performance varies significantly with outdoor temperature.<\/p>\n
Specific parameter considerations:<\/strong><\/p>\n\n- Broader heating curve range required due to air temperature variability<\/li>\n
- Defrost parameters must be configured<\/li>\n
- Bivalence point is critical for cold-climate locations (alpine zones)<\/li>\n
- Acoustic operating limits may apply in residential areas (e.g., nighttime noise restrictions per TA L\u00e4rm in Germany)<\/li>\n<\/ul>\n
Ground-Source Heat Pumps (Erdw\u00e4rme \/ Sole-Wasser-W\u00e4rmepumpen)<\/h3>\n
Source is ground heat via borehole (Erdsondenanlage) or ground collector (Fl\u00e4chenkollektor). Ground temperature is relatively stable.<\/p>\n
Specific parameter considerations:<\/strong><\/p>\n\n- No defrost settings required<\/li>\n
- Source temperature limits must be configured (minimum brine temperature: typically \u22123 \u00b0C)<\/li>\n
- Geothermal protection parameters: limits on heat extraction to prevent ground freezing<\/li>\n
- Regeneration mode: some iDM systems support summer cooling or active regeneration of the ground loop<\/li>\n<\/ul>\n
Water-Source Heat Pumps (Wasser-Wasser-W\u00e4rmepumpen)<\/h3>\n
Source is groundwater or surface water. High and stable COP. Requires well permits and water authority approval.<\/p>\n
Specific parameter considerations:<\/strong><\/p>\n