Electricity can swallow ~65% of textile energy costs and up to 25% of production cost, but premium motors, variable‑speed drives, and smarter HVAC are delivering double‑digit savings with sub‑two‑year paybacks.
In spinning, power is the hidden raw material. Industry studies peg electricity at roughly 65% of textile energy costs, with total energy running 20–25% of production cost (slideshare.net). Inside the mill, electric motors dominate; one audit found motors consume more than 70% of plant electricity (researchgate.net). The ring‑spinning section—draw frames plus ring frames—often carries ~50% of total installed power (link.springer.com), while utilities like humidification and compressed air add up fast; audits show humidification plants alone may use 10–20% of mill energy (slideshare.net). And in some sites, air conditioning and chillers (AC/chillers) have been the whale in the room, reaching about 80% of a mill’s electricity use in one case study (researchgate.net).
That spread of energy sinks makes one thing clear: targeted upgrades can unlock substantial savings (researchgate.net) (researchgate.net).
Motor efficiency and right‑sizing
Because motors supply the bulk of power, premium‑efficiency motors make a direct dent in consumption. IE3/IE4 motors (international efficiency classes for electric motors) draw less power at the same load. In one Indian mill audit, replacing 32 old motors with IE3‑class units cost ≈$56,831 and saved about $54,765/year—roughly a 1.04‑year (≈12.5 months) simple payback (researchgate.net) (researchgate.net). Electricity per kg of yarn (U_kWh/kg, a productivity‑normalized energy metric) fell from ~4.99 to ~4.33, a 13.6% reduction in the energy bill (researchgate.net).
Even small efficiency bumps matter. One study notes replacing a ring‑frame motor from 91.5% to 94.5% efficiency “gave good energy saving” (link.springer.com). Any rewinding or replacement should target the highest efficiency spec feasible. Loading also counts: underloaded motors waste energy. Downsizing an oversized carding‑machine motor saved about 15 kWh/day (≈Rs.30,000/year) for ~Rs.10,000 investment—around a 3–4 month payback (fibre2fashion.com).
Variable‑speed drives on variable loads
Where demand fluctuates—fans, pumps, compressors—VSDs/VFDs (variable speed/frequency drives, electronic drives that vary motor speed to match process need) avoid throttling losses. A humidification plant retrofitted with VFDs on supply and return fans (each fan motor 30–37 kW) eliminated heavy damper throttling; each fan shed ~6–7 kW, delivering ≈2.39 GWh/year savings worth ~$224.5K/year. The VFDs cost ~$205K and paid back in ~11 months (researchgate.net) (researchgate.net).
Fan laws amplify small changes: an audit found a 2% airflow reduction yielded ~5% fan power savings (∼1.6% of total load) (researchgate.net). In compressed air, VSD compressors similarly save 20–30% by avoiding unloaded running; industry case studies routinely show 20%+ compressed‑air savings with VSDs (as summarized in the same audit stream: researchgate.net) (researchgate.net).
Policy requirements and MEPS context
Regulation is nudging the market toward higher efficiency. EU Regulation 2019/1781 requires IE3 for new low‑voltage motors above ~0.75 kW. Indonesia currently lacks a binding motor MEPS; one summary notes “no regulation in place” and only IE1 is “recommended” for 0.375–75 kW motors (scribd.com). Indonesia has introduced MEPS in other areas—e.g., motor‑driven appliances—which suggests future tightening. Indonesian mills can gain an edge by voluntarily adopting IE2/IE3 motors.
HVAC load and setpoint control
Spinning quality depends on tight indoor conditions, typically ~22–24 °C and ~60–70% RH (relative humidity). Yet HVAC (heating, ventilation, and air conditioning) can dominate energy; AC/chillers have been observed at ~30–50% of a mill’s electrical load in practice (ordnur.com), and one audit put AC/chillers at ~80% (researchgate.net). Optimizing HVAC therefore pays off.
Humidification technology upgrades
Traditional steam‑coil or basic spray humidifiers consume substantial energy. Modern multi‑stage and MVR (mechanical vapor recompression, which recycles vapor’s latent heat) approaches use less. Multiple‑effect/MVR humidifiers require only ~0.05–0.15 kWh per kg of water evaporated, versus ~0.7 kWh/kg for older methods (vdoc.pub). Investments in humidification have cut energy “to the tune of 25–60%” (vdoc.pub). Climate‑adaptive controls (“Climo”) that vary fan and pump speeds by ambient conditions have achieved large savings; a South India Textile Research Association (SITRA) report cited paybacks of 1–8 months for 25–60% energy cuts via such controls (vdoc.pub).
Utilities around these systems can include industrial water treatment modules; examples span pretreatment units such as ultrafiltration for surface or groundwater makeup.
Dehumidification and air‑recovery controls
Climate drives the direction: in humid regions, outside air must be dehumidified; in dry, snowy regions it must be humidified. Using precise dewpoint/RH sensors (dewpoint is the temperature at which air becomes saturated) and cycling humidifiers only as needed avoids overshoot. Air‑recovery schemes that treat and reuse return air reduce load; one example “Auto Return Air Cleanser” recycled return air, saving ventilation energy (as documented in the same literature stream: researchgate.net). Optimizing fresh/recirculated airflow matters—an audit observed that even a 2% airflow cut delivered ~5% fan power savings (∼1.6% of total load) (researchgate.net). Matching ventilation to occupancy or heat load (CO₂ or flow‑based control) trims unnecessary conditioning.
Cooling plant efficiency measures
If chillers are installed (industrial refrigeration units delivering chilled water or air), high‑COP (coefficient of performance, a ratio of cooling delivered to power input) machines and variable‑speed compressor drives lift efficiency. Clean coils and filters help maintain design heat transfer. Recovering waste heat—e.g., preheating makeup air with exhaust heat—reduces purchased energy. One plant study reported that best‑practice AC upgrades could save about 20% of AC energy (researchgate.net). Even raising the indoor setpoint by 1–2 °C in winter cut heating/cooling load by ~3–5%. For ventilation and fan motors, applying VFDs follows the same logic as process fans.
Where cooling water or closed‑loop fluids are conditioned, chemical feed skids typically use precise metering; equipment such as an industrial dosing pump is a common building block. Facilities that maintain separate utility areas also rely on supporting equipment for water treatment within those utility trains.
Airside economizers and envelope
When ambient dewpoint is below the indoor setpoint, outside‑air “free cooling” can reduce chiller runtime. Zoning the mill—for example, separating spinning halls from auxiliary spaces—limits over‑conditioning of low‑priority areas. Insulation and door seals limit unwanted heat gains.
Indonesia appliance labels for fans and AC
Indonesia now requires labeling and MEPS for some HVAC components. Ministerial Decree No. 114/2021 mandates energy‑saving labels and efficiency minima for electric fans—for example, a minimum 1.0 efficiency for fans over 12″ diameter (tuv.com). Commercial AC units must also carry a “SKEM” energy label under MoEMR rules (tuv.com). These indicate growing focus on appliance efficiency; mills can align by using labeled, high‑efficiency fans and AC, and by optimizing operation to meet only the necessary load.
Case outcomes and payback
Deploying IE3 motors, trimming oversized machines, adding VFDs on variable loads, and modernizing HVAC controls has repeatedly delivered double‑digit savings in spinning mills. The examples above show energy cost reductions of 10–20% or more (researchgate.net) (researchgate.net), often with paybacks under 1–2 years (researchgate.net) (researchgate.net). Smart HVAC controls alone have delivered 10–30% reductions in HVAC energy in audits (ordnur.com) (researchgate.net), with humidification improvements alone yielding similar orders of savings (vdoc.pub). In a complementary line of industry reporting, an evaporative‑cooling case study notes up to 80% energy saving for textile industry air conditioning (seeleyinternational.com).
Beyond cutting bills and CO₂, these steps reduce peak demand, freeing capacity for production growth. For decision‑makers, the data‑backed outcomes—kWh/kg reduction, $/year savings, ROI—surfaced in energy audits can guide investment in motors, drives, sensors, and HVAC upgrades in spinning plants (researchgate.net) (researchgate.net).
