Modules in PRESS
The PRESS suite consists of a number of modules:
- PRESS-Base: On-line data collection and validation
- PRESS-Prognosis: On-line heat load forecasting
- PRESS-TO: On-line network temperature optimization
- PRESS-PO: On-line production optimization
- PRESS-OP: On-line statistics summarizing the operation of the district heating system
PRESS-Base: Data collection and validation
Since PRESS is an on-line system, the data collection and validation module is needed in all cases. The module collects the necessary data, detects possible errors in the data, and validate the data for the on-line application in the subsequent modules.
PRESS-Prognosis: On-line heat load forecasting
The heat load forecasting is based on meteorological forecasts of primarily ambient air temperature, but the system is also able to use forecasts of radiation and wind speed, if available. The system forecasts the hourly heat load for horizons up to the maximal horizon for which meteorological forecasts are available.
One of the aspects complicating heat load forecasting is the fact that the heat dynamics of the buildings seriously affect the heat demand on an hourly basis. The PRESS system automatically takes this smoothing effect into account. Furthermore, the system continuously adapts to the actual situation by continuously monitoring the consumption. In this way the systems automatically adapts to things such as
- Changes in consumer behaviour
- Changes in the number of consumers
- Changes in the meteorological models
- Changes in the thermal characteristics of the buildings
- Changes in the network
PRESS-TO: On-line network temperature optimization
To reduce heat loss in the distribution network the temperature in the district heating network should be kept low while at the same time keeping the temperature sufficiently high at the consumers and respecting pumping costs.
The online network temperature optimization module achieves this goal by monitoring the temperature at a number of critical points in the network and respecting the pumping costs using the heat load forecasts.
The controller used is very advanced in several aspects, e.g. it is able to handle the time-varying delay from supply point to the critical points and it continuously adapts to system changes.
PRESS-PO: On-line production optimization
This module is typically tailored to the individual district heating system / production facilities because large district heating networks often experience some differences in cost structure. For standard production optimization problems a web-service solution is available. In this case the production system considered must consist of one or more production units (CHP units, boilers, electrical boilers / heat pumps) and a heat storage facility. Based on fuel costs and electricity prices and heat load forecasts the system is then able to determine the optimal production schedule for the coming day.
PRESS-OP: On-line statistics
Using consumption and temperature data this module continuously gathers information about the characteristics of the system and presents this in a comprehensive form. This information includes
- Duration curve of the consumption
- The energy signature, i.e. the expected consumption as a function of air temperature
- The diurnal variation of the consumption.
In this way the persons operating the system can easily monitor the system and take action if undesirable changes occur.