The Comparison, Measuring & Labelling of Energy-efficient Textile Machinery
This interplay of waste heat from the
machine and constant indoor
temperature created by air conditioning
units has not an unimportant influence
on the actual energy consumption,
especially in countries with a high
ambient temperature. These types of
energy consumption are also centrally
based and cannot be recorded with
reference to the process or machine.
The above explanations show that
problems occur simply in the
measurement of energy consumption
– problems which in most cases make
the accurate determination of energy
efficiency impossible.
However, if the textile manufacturer has
installed energy consumption meters
in his sub-processes and records the
consumption, then the energy
optimization of process steps is
always possible for him without
knowing the exact energy efficiency of
his processes.
The energy flows from the balance
envelope can be divided into
convective heat transfer and exhaust
air containing heat.
If the volume of the exhaust air flow
and/or the suction air flow [m3/h] of an
external vacuum system (if used) and
its temperature difference from the
balance envelope temperature is
known, the energy content of the
exhaust air and suction air/exhaust air
or suction air flow can be easily
calculated. The kinetic pressure losses
contained in the exhaust air and
suction air flows can be generally
neglected. The same applies to the
potential energy contained in the
product, i.e. further processed textile
fibres.
If air-conditioning is mandatory or at
least recommended for the operation
of the machine, the manufacturer could
work with indicative figures. The heat
load resulting from the machine’s
operation must be compensated with
a corresponding expense for the air
conditioning. If the exhaust air flowsThe significance of an agreed
and defined work
process/operating point
with their heat load are dissipated as
far as possible directly from the balance
envelope “machine”, then only the
expense in eliminating the convective
heat flow has to be determined for the
proportion of the air conditioning
attributable to the machine. Depending
on the type and configuration of the air
conditioning (direct cooling, adiabatic
air conditioning, plant with a “chiller”,
air exchange rate, etc.) indicative
figures in kWh/kWh can be given for
the “cost of air-conditioning per kW of
heat load”.
As a result of fluctuations in the
operating conditions of the machines
caused by operational reasons,
measurements must be taken either
over a period of several days or by
logging the status parameters over
several hours.
Status parameters are :
1. Sliver and yarn data/spinning
components/negative pressure for
fill-up quantities of yarn chamber/
idle times
2. Setting of the air pressure regulator,
the splicing/opening code and
prisms on winding machines
As different types of energy have to
be included in the balance for different
groups of machines, it could be useful
to specifically distinguish between
machine groups in a similar way to that
employed in en ISO 9902 (noise
emission from textile machinery).
NCM-APRIL 2020
63Consumer goods – such as television
sets – are designed for standard
applications and easily comparable
user requirements. Textile machines,
on the other hand, are generally more
complex. even textile machines of a
particular product type are usually
designed for the different demand
profiles of textile manufacturers. The
demands on the machine result from
the product to be manufactured by the
textile manufacturers and/or the
specific process (conditions of use)
that the manufacturer wishes to use.
Textile machinery is therefore generally
built so that the textile manufacturer
can individually determine his specific
requirements for raw materials, quality
and productivity. These decisions taken
by the textile manufacturer also
directly affect the specific energy use.
The logging and assessment of energy
consumption represents a special
challenge. This means that the energy
consumption of a machine type can
only be determined on the basis of an
agreed (defined) work process/
operating point if you want to avoid
comparing apples with oranges.
Statements on energy consumption
are therefore only valid for each process
which is studied and the parameters
which are defined.
In addition, a statement about energy
consumption is only significant in
relation to the amount produced (kWh/
kg product). This applies equally to the
equivalent of the CO2 footprint (CO2/
kg product).
Meaningful classifications of machines
must first be made for the evaluation
of the energy consumption of textile
machinery. A common process for
assessing energy efficiency must then
be defined for these machine types
along with product and production
parameters of typical production
processes. In order to achieve this,
standard products should be selected