PHPP

Passive House Design-Tools for Calculating Energy Balances


Does energy-conscious design require sophisticated simulations?

This was indeed the case for the first Passive Houses that were completed in 1991. Calculating the energy balance of buildings with very low energy consumption is a demanding task and existing regulations and standards lack the required precision. Nevertheless, we have identified the critical factors for preparing reliable balances - with tools that are simple to use and with acceptable effort in terms of data input. The technique for designing functional passive houses has now been tried, tested and optimized in thousands of cases.


In the News:

2007 Solar Decathlon Winner credits Passivhaus Institut, Darmstadt and PHPP.


The Passive House Planning Package (PHPP)

is a clearly structured design tool that can be used directly by architects and designers.

Several thousand users have already experienced the reliability of the calculation results and the manageability of the tool.


The PHPP includes tools for


    * calculating the U-values (metric reciprocal of R-values) of components with high thermal insulation

    * calculating energy balances

    * designing comfort ventilation

    * calculating the heat load (no heat load climate data contained yet for locations outside the Midwest U.S.)

    * summer comfort calculations

    * and many other useful tools for reliable design of passive houses


First introduced in 1998, PHPP has been continually developed. At the core of the package are worksheets for heating energy balances (heating period or monthly technique), heat distribution and supply, electricity demand and primary energy demand.


New design modules have been added successively, e.g. calculation of window parameters, shading, heating load and summer performance.


The PHPP is continuously validated and refined based on measurements. As part of accompanying scientific research studies, measurements from more than 300 projects have so far been compared with calculation results. Of crucial significance was the CEPHEUS project undertaken as part of the European Thermie program, during which housing developments were constructed according to passive house standards and scientifically accompanied at 14 different European locations (more).


The PHPP energy balance module was shown to be able to describe the thermal building characteristics of passive houses surprisingly accurately. This applies particularly to the new technique for calculating the heating load, which was developed specifically for passive houses.


The following diagram shows the results of a comparison between measurements and PHPP calculations for different passive houses at different locations. It is interesting to note that in all cases, irrespective of the thermal insulation standard of the buildings, there is high (relative) scatter due to user behavior, but the calculations were in excellent agreement with the average measurement results.


Diagram: Comparison of PHPP calculation with consumption measurements in housing developments with low energy and passive houses


Passive house certification is also based on PHPP calculations. The current PHPP 2004 contains the following worksheets:


Verification

Building description, selection of the calculation method, summary of results.


Areas

Central input sheet for entering building envelope data. For greater clarity, the entries are automatically consolidated into surface groups and their heat losses are summarized. U-values are also assigned in the areas worksheet via convenient selection menus. This significantly simplifies data management. Thermal bridges and reference area are also entered here.


U-List

List of calculation results from the U-Values worksheet, building elements database


U-Value

Calculation of building element U-values: Thermal transmittance calculations in accordance with DIN EN ISO 6946, including wedge-shaped components and composite constructions like wood-framed exterior walls


Ground

Calculation of heat losses through the ground, based on algorithms of EN 13370 that have been revised and extended. The worksheet includes algorithms for dealing with thermal bridges and groundwater effects.


Windows

Determination of UW and exterior radiation considering the effects of geometry, orientation, thermal properties of glazing and frame, thermal bridge heat loss coefficients and climate.


WinTyp...

Lists of glazing and window frames with all necessary characteristics. Contains a database of Passive House components.


Shading

Determination of shading factors considering e.g. balconies, neighboring buildings and the window reveal.


Ventilation

Sizing the ventilation system from exhaust and supply air requirements, infiltration air change rate and actual efficiency of heat recovery, entry of pressurization test results.


Annual Heat Requirement

Calculation of the annual heat requirement following the energy balancing procedure in accordance with EN 832 (annual method). The worksheet shows a clearly structured energy balance.


Monthly Method

Calculation of the annual heat requirement according to EN 832 monthly method, graphic display of monthly balance.


Heat Load

Calculation of the nominal building heat load using a two-design-day method that is appropriate for Passive Houses. A technique for checking whether the thermal output from the central heat supply system is sufficient for (critical) individual rooms has been added.


Summer

Calculation of the frequency of overheating as a measure of summer comfort


Shading-S

Determination of shading factors for the summer


SummVent

Estimation of air flow rates for natural ventilation during the summer period


DHW + Distribution

Heat loss calculation of the distribution systems (heating, DHW); calculation of the useful heat requirement of DHW and storage losses


Solar DHW

Calculation of the fraction of DHW provided by the solar system


Electricity

Calculation of household electricity and primary energy requirements of the PH building


Auxiliary Electricity

Calculate electricity and primary energy requirements of auxiliary electricity users (circulation pumps, etc.)


PE Value

Selection of heat generators, calculation of the primary energy and CO2 characteristic values from the present results


Compact

Calculation of the performance of a compact unit using an electric heat pump for space heating and DHW for the project-specific boundary conditions


Boiler

Calculation of the performance of heat production with standard boilers (low temperature or condensing, gas-, oil- or wood-fired) for the project-specific boundary conditions


District Heat

Calculation of final energy and primary energy requirements associated with district heating


Climate Data

Climate regions may be selected from over 200 locations in Europe and North America. User-defined data can easily be used, too.


IHS

Calculation of the internal heat gains


Data

Table of PE factors, etc.