Additional Functions; Billing Date Values; Data Logging; Simultaneous Readout - INTEGRA Metering CALEC ST III User Manual

Operation
6.8

Additional functions

6.8.1

Billing date values

With the 12 freely programmable billing date values, the indexes can be memorized (e.g. monthly) for de-
fined dates and consulted at any time [}p. 42].
6.8.2

Data logging

The CALEC® ST III can record up to 500 data records in a ring buffer at intervals of minutes, hours, days,
weeks, months [}p. 43].
6.8.3

Simultaneous readout

In a plant with many meters, a considerable time difference between readings can occur if these are read out
sequentially. CALEC® ST III avoids this problem with the "Freeze" command. A broadcast command in-
structs all meters simultaneously to store the required value after which they can be read out sequentially.
6.8.4

Low-flow OFF function

The system is factory-adjusted to carry out an energy calculation as soon as a temperature difference of >0
(when measuring heat) or <0 (when measuring cold) is detected. If, for example, a circulation conduit carries
large quantities of heat transfer medium with a very low temperature difference over a long period of time,
this can lead to significant reading errors in temperature measurement. The so-called "low flow OFF func-
tion" can be activated to avoid this, ensuring that energy is only detected when a pre-defined temperature
difference is exceeded.
6.8.5 Energy metering in heating / cooling systems
The "bi-directional energy metering" (BDE) option al-
lows emitted energy to be metered even in twin-con-
duit networks that perform a combined heating and
cooling function. The measurement readings for
heating and cooling are recorded separately for their
corresponding cost-calculation purposes.
6.8.6 Recording of „heat return"
The „Tariff Return Limit" (TGR) option can be used to set a limit for the return temperature of the heat
quantity. If this limit is exceeded, the flow is „returned" to the supply network and thus reduces efficiency.
6.8.7

Heat carriers with frost protection additives

The below-freezing temperatures involved in running a refrigeration plant require the use of additional frost
protection. This poses an insurmountable problem for many conventional heat meters, as has been investi-
gated in detail in such publications as PTB Report PTB- ThEx-24 of June 2002.
The "Glycol-based heat transfer medium" option available with CALEC® ST III ensures that metering is accu-
rate even in these situations, as energy and volume can be calculated with a sliding scale of values for den-
sity and heating capacity for each temperature, independently of that temperature. CALEC® ST III gives ac-
curately polynomial readings for the physical characteristics of 11 widely used heat transfer liquids with re-
spect to concentration and temperature.
Only the heat transfer medium and concentration are established at start-up:
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