Condition and requirement for the use of this manual

All information in this manual represents the latest status at the present time. Glen Dimplex Germany does not accept any liability or guarantee that the information and data provided are up-to-date, correct or complete. All claims for damages are excluded. As far as this is not legally possible, these claims are limited to gross negligence and intent.

Glen Dimplex Germany reserves the right to make changes, deletions or additions to the information and data provided and to download them or view them on the website www.glendimplex.de to provide. All rights, in particular copyrights, patent rights, utility models and / or trademark rights, are held by Glen Dimplex Germany.

introduction

This project planning manual (PHB) provides the most important information in connection with the planning, operation and construction of a heat pump system. It serves as a reference work for the planner and installer, but can also be used as a document for training or to prepare for a technical or advisory meeting. It cannot and should not replace technical expertise. It is the responsibility of each user to carefully check the information he uses, in particular to ensure that it is up-to-date, correct and complete.

Notes on use:

The illustrations and descriptions contained in this manual serve to develop an understanding of all components contained in a heat pump system. The illustrations and schemes are therefore concentrated on the essentials and are not to be understood as complete assembly instructions.

These can be found in the product documents of the respective heat pump or the system accessories, the device-related planning documents or the electrical or hydraulic integration schemes.

Furthermore, information on the manual implementation has only been included in this manual if specific features have to be observed when installing a heat pump system.

1.1 Why a Heat pump?

The high proportion of fossil fuels in our energy supply has serious consequences for our environment. When they are burned, in addition to large amounts of carbon dioxide, other pollutants such as carbon monoxide, unburned hydrocarbons, sulfur dioxide, particles e.g. soot and nitrogen oxides are released in large quantities.

Space heating with fossil fuels contributes significantly to the emission of pollutants, since complex exhaust gas cleaning measures - as in modern power plants - are not provided. Due to the limited supplies of oil and gas, the high proportion of fossil fuels in our energy supply is problematic.

In the course of the next few decades, the phase-out of the use of fossil fuels for the generation of electrical energy towards renewable energy generation will continue to be driven forward.

Since the Heat pump only a small amount of electricity is required to temper the heat obtained from air, water or earth so that it can be used for heating purposes, it has a significantly lower rate of loss than oil or gas heating.

A heat pump is more than just a heater. The advantages of a heat pump at a glance:

• more efficiency

  • EU energy label: Only heat pumps and heat pump systems consistently achieve the highest label classes.

  • Energy Saving Ordinance (EnEV): Houses with heat pumps meet the more stringent energy standards now and in the future.

  • The annual operating costs of a heat pump are extremely low. A small percentage of these are linked to electricity prices.

  • Special low-cost electricity tariffs are available.

• more climate protection

  • Heat pumps cause significantly fewer CO2 emissions than a conventional boiler (up to 90 percent less than gas and oil heating).

  • Electricity is getting greener and greener - and with it the heat pump.

  • Energy supplier is environmentally friendly and almost inexhaustible.

• more independence

  • individual (PV self-consumption, power-to-heat / thermal storage)

  • for all of Germany through fewer oil and natural gas imports

  • Heat pumps are almost maintenance-free.

  • The operational safety of heat pumps is very high.

• more quality of life

  • cozy warmth and comfortable cooling in one device

  • clean energy source, space-saving technology

  • can be used for heating in almost any type of building

1.1.1 What does the heat pump do?

The heat pump is a "transport device" that brings the environmental heat, which is available free of charge, to a higher temperature level.

1.1.2 How does the heat pump convert low-temperature heat into high-temperature heat?

It extracts stored solar heat from the environment - soil, water (e.g. groundwater) and air (e.g. outside air) and transfers this to the heating and hot water circuit in addition to the drive energy in the form of heat.

Heat cannot pass from a colder body to a warmer one by itself. It always flows from a body with a high temperature to a body with a lower temperature (second law of thermodynamics). Therefore, the heat pump must bring the heat energy absorbed from the environment using high-quality energy - e.g. electricity for the drive motor - to the temperature level necessary for heating and hot water preparation.

The heat pump actually works like a refrigerator. That means with the same technology, but with the opposite benefit. It extracts heat from a cold environment, which can be used for heating and hot water.

1.2 Terms

1.2.1 Defrost

Control routine for removing frost and ice on evaporators of air / water heat pumps by supplying heat. Air / water heat pumps with reverse circulation are characterized by need-based, fast and energy-efficient defrosting.

1.2.2 Bivalent-parallel operation

The bivalent operating mode (nowadays usually bivalent-parallel operation) works with two heat generators (two energy sources), i.e. the heat pump covers the heat output requirement up to the determined limit temperature and is then supported in parallel by a second energy generator.

1.2.3 Bivalent-renewable operation

The bivalent regenerative mode of operation enables the integration of regenerative heat generators such as wood or thermal solar energy. If energy from renewable energies is available, the heat pump is blocked and the current heating, hot water or swimming pool requirement is served from the regenerative storage.

1.2.4 Carnot coefficient of performance

The ideal comparison process for all heat work processes is the Carnot process. This ideal (imaginary) process results in the theoretical efficiency or, in comparison with the heat pump, the theoretically highest coefficient of performance. The Carnot coefficient of performance only applies the pure temperature difference between the warm and the cold side.

1.2.5 CO₂-Equivalent (global warming potential - GWP)

The global warming potential (GWP) or CO₂-Equivalent to one chemical compound is a measure of their relative contribution to the Greenhouse effect, so their mean warming effect is the Earth atmosphere over a certain period of time (usually 100 years). It indicates how much a certain Dimensions one Greenhouse gas compared to the same mass of CO₂ to the global warming contributes.

For example, this is CO₂-Equivalent for methane with a time horizon of 100 years 28; This means that within the first 100 years after its release, one kilogram of methane contributes 28 times as much to the greenhouse effect as one kilogram of CO₂. at Nitrous oxide this value is 265.

1.2.6 D-A-CH seal of approval

Certificate for heat pumps in Germany (D), Austria (A) and Switzerland (CH) that meet certain technical requirements, have a 2-year guarantee, guarantee spare parts availability for 10 years and whose manufacturer has a comprehensive customer service network. In addition, the seal of approval certifies the seriality of a heat pump series.

1.2.7 EnEV

The Energy Saving Ordinance (EnEV) regulates measures for saving energy in buildings in Germany. In addition to the basic requirements for newly constructed buildings, deadlines are also set for the replacement of outdated heating technology.

1.2.8 Energy efficiency

Energy efficiency is a measure of the amount of energy used to achieve a specific benefit. A process is efficient when a certain benefit can be achieved with a minimal expenditure of energy. For heating technology, this means: "Comfortable room temperatures with minimal use of energy."

The energy efficiency of a building (heating and drinking water heating) is expressed in terms of "primary energy", as this is in contrast to the final energy requirement - i.e. the amount of energy (liters of heating oil / m³ Natural gas / kWh electricity) that you buy from your energy supplier - also takes the upstream process chain into account. The primary energy requirement also includes the energy that was required for the production, conversion and distribution of the energy source.

In order to make the energy demand and the energetic quality of different buildings comparable, the primary energy demand is allocated to the living space of a house. The Energy Saving Ordinance (EnEV) regulates the maximum amount of primary energy per square meter and year (kWh / (m²a)) a newly constructed building may use for heating and domestic hot water.

1.2.9 Energy label

In order to make a comparison of different heat generators that use different heating energy sources, the different room and combination heaters and water heaters are divided into the respective energy efficiency classes on the basis of the seasonal space heating energy efficiency or the water heating energy efficiency, the latter depending on the load profile.

To calculate the seasonal space heating or hot water heating energy efficiency, the heat requirement covered by the heater or the system is related to the annual energy requirement required for this. The resulting percentage value determines the efficiency class achieved.

In order to make the different heat generators comparable, they are divided into the respective energy efficiency classes on the basis of the seasonal space heating energy efficiency or the water heating energy efficiency.

With the EU energy label, only heat pumps and heat pump systems achieve the highest efficiency class. Even today, a heat pump with an annual coefficient of performance (JAZ) of 2.14 or better causes fewer CO2 emissions than a conventional gas condensing boiler with an efficiency of 90%. And because the proportion of renewable electricity in our grids continues to increase, heat pumps will become even more climate-friendly over the years.

1.2.10 Energy label overview:

1.2.10.1 Product label and compound system label

A basic distinction is made between product labels issued exclusively by the manufacturer and composite system labels. Product labels are only available for pure heat generators, e.g. hot water heat pumps, heat pumps for space heating and DHW heating or condensing boilers. In a compound system, these are combined with one or more additional components. Compound system labels can be issued by manufacturers, wholesalers or craftsmen.
Due dates

Fig. 0.1: Summary table for adapting the energy label

1.2.10.2 Overview: compact EU energy label

There are three different reference dates for the mandatory use of the energy label, as a step-by-step tightening of the efficiency scales for the product labels of space heaters and water heaters is planned.

• From the September 26, 2015 All space heating devices must have a product label with an efficiency scale ranging from A ++ to G. For the water heating energy efficiency of combination heaters and for pure water heaters, a scale with classes A to G is mandatory.

• From the 26th September 2017 A product label that includes efficiency classes A + to F becomes mandatory for pure water heaters.

• From the 26th September 2019 Space heating systems must also bear the "Label II", which includes classes A +++ to D. In addition, the scale for the water heating energy efficiency of combination heaters now also includes classes A + to F.

• The energy label classes for Compound systems include from September 26, 2015 Classes A +++ to G for room and combination heaters as well as hot water heaters.

From the Deadline September 26, 2015 Space heaters, combination heaters, pure water heaters and compound systems must bear an efficiency label. All space heaters must have efficiency classes A ++ to G from this date. From this day on, the labels for interconnected systems carry efficiency classes A +++ to G.

1.2.10.3 Which devices are affected by the energy label

So that a comparison of different technologies is possible, the EU directives on energy labeling and ecodesign summarize certain product groups in so-called "lots". With the amendment of the directives, not only energy-consuming, but also energy-related products (ErP) are considered.

Lot 1 concerns room and combination heaters as well as composite systems made up of these devices and other components. Devices and systems for space heating or for combined space heating and drinking water heating with a nominal heat output of up to 70 kW are affected by the labeling.

The regulations in lot 2 apply to water heaters with a nominal heat output of up to 70 kW and to hot water storage tanks with a storage volume of no more than 500 liters. In addition, the specifications also apply to combinations ("compound systems") of water heaters with a nominal heat output of up to 70 kW and solar devices.

In addition to heat pumps and low-temperature heat pumps, the scope of the two lots also includes fossil-fired boilers (natural gas / heating oil) and CHP (combined heat and power) systems. Solid fuel boilers (wood, pellets) are not covered by these regulations and therefore cannot be compared with the other technologies.

1.2.10.4 Compound system label

Compound systems are always a combination of the respective space heater, combination heater or water heater and one or more of the following components:

• Temperature controller

• thermal solar system

• Storage

• additional heat generator

Compound systems usually achieve higher efficiency values than are indicated by the product label of the pure heat generator. For example, a condensing boiler, which for physical reasons can achieve a maximum of efficiency class A on its own, in combination with a temperature controller and solar system, an efficiency class A + can be achieved. However, deterioration is also conceivable, for example in the case of a heat pump that is combined with fossil heating technology as an additional heat generator.

The labels for the compound systems can be issued by the manufacturers, wholesalers and the specialist trade. Information on the efficiency class is required when preparing the offer. The data required for the calculation must be provided by the manufacturers of the individual products or components.

There are a total of 14 different labels for the individual technologies and integrated systems for room and combination heaters alone. What can be seen on the individual labels is explained below using the example of the labels for heat pumps.

Because a heat pump with intelligent control is, by definition, a composite system, most heat pumps - even though they are optically a single device - are in practice supplied with two labels. For example, a heat pump with intelligent control is simultaneously marked with A + or A ++ on the product label and with A +++ on the composite system label.

1.2.10.5 Label for space heaters (product label)

In addition to information on the manufacturer and model, the product label must also contain the energy efficiency classes, the nominal heat output (for average, warmer and colder climates) and information on the sound power levels.

Fig.0.2: Product label (label I) for a space heater with heat pump (from September 2015)

1.2.10.6 Label for combination heaters (product label)

The labels for heat pumps for combined space heating and drinking water heating contain, in addition to the column for space heating energy efficiency, a column for water heating energy efficiency, which ranges from A to G for label I and from A + to F for label II.

1.2.10.7 Label for interconnected systems

In contrast to the product labels, the efficiency scales of the composite system labels for heating devices and water heaters already include classes A +++ to G from September 26, 2015 May contain storage and another space heater.

Fig. 0.5: Label for compound systems made up of space heaters and other components (from September 2015)

1.2.10.8 Comparison of the efficiency of systems and products

_{* Seasonal space heating energy efficiency for all space heaters in combination with temperature controller class VIII}

Fig. 0.6: Comparison of the efficiency of different heat generators

1.2.11 EVU blocking times

The use of special heat pump tariffs of the respective local EVU requires a supply of electrical energy that can be switched off by the EVU. The power supply can be interrupted e.g. for 3 x 2 hours within 24 hours. Therefore, the daily heating work (daily heat quantity) must be applied within the time in which electrical energy is available.

1.2.12 Expansion valve

Component of the heat pump between the condenser and evaporator to lower the condensing pressure to the evaporation pressure corresponding to the evaporation temperature. In addition, the expansion valve regulates the amount of refrigerant injected depending on the evaporator output.

1.2.13 Limit temperature / equilibrium point

Outside temperature at which the 2nd heat generator in mono-energetic (electric immersion heater) and bivalent parallel operation (e.g. boiler) is switched on depending on demand and serves the heat demand of the house together.

1.2.14 Inverter

The inverter principle is based on the fact that the performance of the heat pump compressor is controlled by a frequency converter ("inverter"). This mode of operation is also Modulation or heat pumps modulating the corresponding heat pumps called.

Inverters are used in heat pumps for stepless power control depending on the heating requirement. The compressor motor rotates faster or slower by varying the alternating current frequency. As a result, output-controlled heat pumps always work at the optimal operating point and produce exactly as much heat as is required at any time.

Fig. 0.7: Comparison of inverter and "on-off" heat pumps

Conventional heat pumps without frequency control or inverters (fix-speed heat pumps) switch on when heat is required and run at full load. Once the requirement has been reached or the desired amount of heat is produced, the heat pump switches itself off again. A heat pump with an inverter, on the other hand, continuously adapts its output to the demand, so that it does not work with the full heat pump output, but only with the output that is sufficient for the requirement level.

1.2.15 Annual work rate

The ratio between the amount of thermal energy released by the heat pump system within a year and the amount of electrical energy supplied corresponds to the annual coefficient of performance. It relates to a specific system, taking into account the design of the heating system (temperature level and temperature difference) and must not be equated with the coefficient of performance.

1.2.16 Annual expenditure figure

The effort figure corresponds to the reciprocal of the work figure. The annual expenditure figure indicates what expenditure (e.g. electrical energy) is necessary to achieve a certain benefit (e.g. heating energy). The annual expenditure figure also includes the energy for auxiliary drives. The VDI guideline VDI 4650 exists for calculating the annual expenditure figure.

1.2.17 Cooling capacity

Amount of heat that is extracted from the environment by the evaporator of a heat pump. The heating capacity of the compressor results from the electrical power consumption and the supplied cooling capacity.

1.2.18 refrigerant

The working substance of a refrigeration machine or heat pump is referred to as refrigerant. The refrigerant is characterized as a fluid that is used to transfer heat in a refrigeration system and that absorbs heat at low temperature and low pressure and gives off heat at higher temperature and pressure. Safety refrigerants are refrigerants that are non-toxic and non-flammable.

Table 0.1: Table of substances: Commercially available refrigerants for heat pumps

1.2.19 Performance figure (COP = Coefficient of Performance)

The ratio between the heat output by the heat pump and the electrical power consumed is expressed by the coefficient of performance, which is calculated under standardized conditions (e.g. for air A2 / W35, A2 = air inlet temperature +2 ° C, W35 = heating water flow temperature 35 ° C and proportional pump output ) is measured in the laboratory according to EN 255 / EN 14511. A coefficient of performance of 3.2 therefore means that 3.2 times the electrical power used is available as usable heat output.

1.2.20 Iog p-h diagram

Graphic representation of the thermodynamic properties (enthalpy, pressure, temperature) of working media.

1.2.21 Monoenergetic operation

In principle, the monoenergetic mode of operation is a bivalent-parallel mode of operation in which only one energy source is used, usually electricity. The heat pump covers a large part of the required heat output. On a few days when the outside temperature is low, an electric heating rod supplements the heat pump.

The dimensioning of the heat pump for air / water heat pumps is usually based on a limit temperature (also called the bivalence point) of approx. 5 ° C.

1.2.22 Monovalent operation

This operating mode covers the heating requirements of the building one hundred percent all year round. This type of application should be given preference as far as possible.

Usually, brine / water or water / water heat pumps are operated monovalently.

1.2.23 Buffer storage

The installation of a heating water buffer storage tank is generally recommended in order to extend the running times of the heat pump when there is little heat demand. A buffer storage tank is essential for air / water heat pumps in order to guarantee a minimum runtime of 10 minutes during defrosting (control routine to remove frost and ice on the evaporator).

1.2.24 SCOP

Abbreviation for "Seasonal Coefficient of Performance". The SCOP indicates the annual coefficient of performance of a heat pump within different operating states, which are weighted according to climate zones. Here, the outside temperatures of 12 °, 7 °, 2 ° and -7 ° Celsius are used for the measurement The additional division into three climate zones, Northern, Central and Southern Europe, enables an even more precise assessment of the performance efficiency.

The SCOP can be converted using the following equation using the eta (s) value:

eta (s) = 1 / 2.5 x SCOP x 100 -3

1.2.25 SG Ready

The "SG Ready" label relates to the heat pump / series including the control technology used to control it, as well as interface-compatible system components. The label is awarded for Germany, Austria and Switzerland.

The SG Ready label helps to identify heat pumps that can be addressed via a defined interface for the purpose of load management for grid serviceability. This interface can be used, for example, by network operators to control the device. The interface can also be used, for example, for control with the aim of achieving the highest possible self-consumption in combination with a photovoltaic system.

Requirements for the SG Ready label

Heating heat pumps
Heating pumps must have a controller that covers four operating states:
Operating state 1 (1 switching state, with terminal solution: 1: 0): This operating state is downward compatible with the EVU blocking, which is often switched at fixed times, and comprises a maximum of 2 hours of "hard" blocking time. 
Operating condition 2 (1 switching state, with terminal solutions: 0: 0): In this circuit, the heat pump runs in energy-efficient normal mode with a proportionate amount of heat storage tank filling for the maximum two-hour power company block. 
Operating status 3 (1 switching state, with terminal solution 0: 1): In this operating state, the heat pump runs within the controller in increased operation for room heating and hot water generation. This is not a definitive start-up command, but a switch-on recommendation based on today's increase. 
Operating status 4 (1 switching state, with terminal solution 1: 1): This is a definitive start-up command, insofar as this is possible within the framework of the control settings. For this operating state, different control models must be set on the controller for different tariff and usage models:

Variant 1: The heat pump (compressor) is actively switched on.

Variant 2: The heat pump (compressor and electrical auxiliary heating) is actively switched on, optional: higher temperature in the heat storage tanks. The room temperature can optionally be used as a reference variable for regulating the system temperatures (flow and return temperature). Blocking the heat pump with a room thermostat depending on the room temperature is not sufficient.

Domestic water heat pumps

Hot water heat pumps must have a controller which, by means of an automatic control, enables the target hot water temperature to be increased for the purpose of thermal storage.

1.2.26 sound

Essentially, a distinction is made between the two types of airborne sound and structure-borne sound. Airborne sound is sound that propagates through the air. Structure-borne sound spreads in solid substances or liquids and is partially emitted as air-borne sound. The audible range of the sound is between 16 and 16,000 Hz.

1.2.27 Sound pressure level

The sound pressure level, measured in the surrounding area, is not a machine-specific variable, but a variable that depends on the measuring distance and the measuring location.

1.2.28 Sound power level

The sound power level is a specific, machine-specific and comparable parameter for the radiated acoustic power of a heat pump. The sound immission level to be expected at certain distances and acoustic surroundings can be estimated. The standard provides for the sound power level as a noise characteristic value.

1.2.29 Brine / brine liquid

Frost-proof mixture of water and frost protection concentrate on a glycol basis for use in geothermal collectors or geothermal probes.

1.2.30 evaporator

Heat exchanger of a heat pump in which a heat flow is withdrawn from the heat source (air, groundwater, soil) by evaporation of a working medium at low temperature and low pressure.

1.2.31 Compressor (Compressor)

Machine for the mechanical conveyance and compression of gases. Compression increases the pressure and temperature of the refrigerant significantly.

1.2.32 Condenser

Heat exchanger of a heat pump in which a heat flow is given off by liquefying a working medium.

1.2.33 Heat demand calculation (heating load)

In the case of heat pump systems, precise dimensioning is essential, as an oversized system would cause increased energy costs and negatively affect efficiency. The determination of the heat requirement is based on country-specific standards.

The specific heat demand (W / m²) is multiplied by the living space to be heated. The result is the total heat demand, which includes both the transmission and ventilation heat demand.

1.2.34 heat recovery system

The heat utilization system has a decisive influence on the efficiency of the heat pump heating system and should get by with the lowest possible flow temperatures. It consists of the device for transporting the heat transfer medium from the warm side of the heat pump to the heat consumers. In a single-family house, for example, it consists of the pipeline network for heat distribution, the low-temperature heating or the radiators including all additional equipment.

1.2.35 heat pump system

A heat pump system consists of the heat pump and the heat source system. In the case of brine and water / water heat pumps, the heat source system must be developed separately.

1.2.36 Heat pump heating system

Complete system, consisting of the heat source system, the heat pump and the heat utilization system.

1.2.37 heat source

Medium from which heat is extracted by the heat pump.

1.2.38 Heat source system (WQA)

Device for extracting heat from a heat source and transporting the heat carrier between the heat source and the heat pump, including all additional devices.

1.2.39 heat transfer medium

Liquid or gaseous medium (e.g. water, brine or air) with which heat is transported.

1.2.40 Wall heating

Wall heating with water flowing through it acts like a large radiator and has the same advantages as underfloor heating. As a rule, 25 ° C to 28 ° C is sufficient for heat transfer, which is mainly brought into the room as radiant heat.

1.3 Formula symbols

size	symbol	unit	Other units (definition)
Dimensions	m	kg
density		kg / m3
Time	t	s H	1h = 3600s
Volume flow	V	m3/ s
Mass flow	m	kg / s
force	F.	N	1 N = 1kg m / s2
pressure	p	N / m2; Pa	1 Pa = 1 N / m2 1 bar = 105 Pa
Energy, work, heat (amount)	E, Q	J kWh	1 J = 1 Nm = 1 Ws = 1kg m2/ s2 1 kWh = 3600 kJ = 3.6 MJ
Enthalpy	H	J
(Heating capacity Heat flow	P.	W. kW	1 W = 1 J / s = 1 Nm / s
temperature	T	K ° C	Absolute temperature, temperature difference, temperature in ° Celsius
Sound power Sound pressure	L.WA L.PA	dB (re 1pW) dB (re 20 microPa)	Sound pressure level Sound power level
Efficiency		-
Performance figure	(COP)	-	Performance figure
Work rate	ß	-	e.g. annual performance figure
spec. Heat content	c	J / (kg K) kWh / (m3 K)	e.g. c(Water) = 4182 J / (kg K) or 1.1617 kWh / (m3 K)

Table 0.2: Table overview of important formula symbols

1.4 Greek letters

		alpha			Iota			Rho
		beta			Kappa			Sigma
		gamma			Lambda			dew
		delta			Mu			Ypsilon
		epsilon			Nu			Phi
		Zeta			Xi			Chi
		Eta			Omicron			Psi
		Theta			pi			omega

Table 0.3: Table overview of Greek letters

1.5 Energy content of different fuels

1. _{Calorific value Hi (formerly Hu): The calorific value Hi (also known as the lower calorific value) is the amount of heat that is released during complete combustion, when the water vapor produced during combustion escapes unused}

2. _{Calorific value Hs (formerly Ho): The calorific value Hs (also known as the upper calorific value) is the amount of heat that is released during complete combustion, when the water vapor generated during combustion is condensed and the heat of evaporation is thus usable.}

Table 0.4: Energy content of various fuels

1.6 Conversion tables

1.6.1 Energy units

Table 0.5: Conversion table for energy units

1.6.2 Performance units

Table 0.6: Conversion table for power units

1.6.3 Pressure

Tab. 0.7: Conversion table for pressure units

1.6.4 length

Table 0.8: Conversion table for length units

1.6.5 Powers

Tab. 0.9: Table overview of potencies

1.7 Planning and installation aids

1.7.1 Pipe dimensioner

In order to minimize pressure losses and thus the power requirement for circulation pumps, the pipe cross-sections must be dimensioned appropriately large. The specific pressure loss per meter of pipe and the flow velocity of the medium in the pipe, based on the nominal volume flow, are the design criteria for this.
The following guide values should not be exceeded:

• dp_Max = 120 Pa / m

• of pipelines DN 10 to DN 65 w_Max = 0.7 m / s

• from pipes DN 80 to DN 125 w_Max = 1.2 m / s

• from pipes DN 150 w_Max = 2.0 m / s

Fig. 0.8: Dimplex pipe dimensioner

1.7.2 Master copy for the experimental determination of the actually required system temperature

Fig. 0.9: Diagram for the experimental determination of the system temperature actually required

Perform the following steps during the heating season at different outside temperatures:

1. Set the room thermostats in rooms with high heat requirements (e.g. bathroom and living room) to the highest level (valves fully open!).

2. Reduce the flow temperature on the boiler or the mixer valve until the desired room temperature of approx. 20-22 ° C is reached (note the inertia of the heating system!).

3. Note the flow and return temperatures as well as the outside temperature in the table.

4. Transfer the measured values to the diagram.

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